Electrochemical CO₂ reduction (ECR) driven by intermittent renewable energy sources is an emerging technology to achieve net-zero CO₂ emissions. Tandem electrochemical CO₂ reduction (T-ECR), employs tandem catalysts with synergistic or complementary functions to efficiently convert CO₂ into multi-carbon (C₂₊) products in a succession of reactions within single or sequentially coupled reactors. However, the lack of clear interpretation and systematic understanding of T-ECR mechanisms has resulted in suboptimal current outcomes. This review presents new perspectives and summarizes recent advancements in efficient T-ECR across various scales, including synergistic tandem catalysis at the microscopic scale, relay tandem catalysis at the mesoscopic scale, and tandem reactors at the macroscopic scale. We begin by outlining the principle of tandem catalysis, followed by discuss on tandem catalyst design, the electrode construction, and reactor configuration. Additionally, we address the challenges and prospects of tandem strategies, emphasizing the integration of machine learning, theoretical calculations, and advanced characterization techniques for developing industry-scale CO₂ valorization.

To enhance the efficiency of green energy harvesting and pollutant degradation, significant efforts are focused on identifying highly effective catalysts. Metal-nitrogen-carbon single-atom catalysts (M-N-C SACs) have emerged as pivotal in catalysis due to their unique geometric structures, electronic states, and catalytic capabilities. Notably, the incorporation of magnetic elements at the active centers of these single-atom catalysts has garnered attention for their role in efficient electrochemical conversions. The orientation of spin states critically influences the adsorption and formation of reactants and intermediates, making the precise control of spin alignment and magnetic moments essential for reducing energy barriers and overcoming spin-related limitations, thereby enhancing catalytic activity. Thus, understanding the catalytic role of spin and modulating spin density at M-N-C single-atom centers holds profound fundamental and technological significance. In this review, we elucidate the fundamental mechanisms governing spin states and its influence in electrocatalysis. We then discuss various strategies for adjusting the spin states of active centers in the M-N-C SACs and the associated characterization techniques. Finally, we outline challenges and future perspectives of spin regulation for high-performance catalysts. This review provides deep insights into the micro-mechanisms of catalytic phenomena and offers a roadmap for designing spin-regulated catalysts for advanced energy applications.

Heme peroxygenases exhibit remarkable catalytic versatility in facilitating a wide array of oxidative reactions under mild conditions, eliminating the need for coenzymes and intricate electron transport systems. This unique character underscores their essentiality and potential as promising tools in synthetic biology. Recent advancements in enzyme engineering have significantly enhanced the catalytic performance of both natural and artificial peroxygenases. Extensive engineering efforts have been directed towards unspecific peroxygenases and fatty acid peroxygenases, aiming to expand their substrate specificities, and enhance reaction selectivities, as well as increase enzyme stability. Furthermore, innovative strategies such as dual-functional small molecule-assisted systems and H₂O₂ tunnel engineering have been harnessed to transform P450 monooxygenases into highly efficient peroxygenases, capable of catalyzing reactions with a variety of unnatural substrates. This review consolidates the latest progress in the engineered and artificial heme peroxygenases, emphasizing their catalytic performances as potent biocatalysts for sustainable organic synthesis.

The objective of electrochemical CO₂ reduction technologies (ECRs) is notably audacious: to revolutionize the market by generating fuel and essential chemicals at a more competitive price than petrochemicals can offer, all while prioritizing environmental sustainability. To expedite the commercialization of ECR technology, we discuss here how ECR can reshape the industry landscape through 2e^- pathways.

Light-driven CO₂ reduction reaction (CO₂RR) to value-added ethylene (C₂H₄) holds significant promise for addressing energy and environmental challenges. While the high energy barriers for *CO intermediates hydrogenation and C−C coupling limit the C₂H₄ generation. Herein, Cu_xP/g-C₃N₄ heterojunction prepared by an in-situ phosphating technique, achieved collaborative photocatalytic CO₂ and H₂O, producing CO and C₂H₄ as the main products. Notably, the selectivity of C₂H₄ produced by Cu_xP/g-C₃N₄ attained to 64.25%, which was 9.85 times that of Cu_xP (6.52%). Detailed time-resolution photoluminescence spectra, femtosecond transient absorption spectroscopy tests and density functional theory (DFT) calculation validate the ultra-fast interfacial electron transfer mechanism in Cu_xP/g-C₃N₄ heterojunction. Successive *H on P sites caused by adsorbed H₂O splitting with moderate hydrogenation ability enables the multi-step hydrogenation during CO₂RR process over Cu_xP/g-C₃N₄. With the aid of mediated asymmetric Cu and P dual sites by g-C₃N₄ nanosheet, the produced *CHO shows an energetically favorable for C−C coupling. The coupling formed *CHOCHO further accepts photoexcited efficient e⁻ and *H to deeply produce C₂H₄ according to the C2+ intermediates, which has been detected by in-situ diffuse reflectance infrared Fourier transform spectroscopy and interpreted by DFT calculation. The novel insight mechanism offers an essential understanding for the development of Cu_xP-based heterojunctions for photocatalytic CO₂ to C2+ value-added fuels.

Regulating the interfacial charge transfer is pivotal for elucidating the kinetics of engineering the interface between the light-harvesting semiconductor and the substrate/catalyst for photoelectrocatalytic water splitting. In this study, we constructed a superior Ti-doped hematite photoanode (TiFeO) by employing SnO_x as an electron transfer mediator, partially oxidized graphene (pGO) as a hole transfer mediator, and molecular Co cubane as a water oxidation catalyst. The Co/pGO/TiFeO/SnO_x integrated system achieves a photocurrent density of 2.52 mA cm⁻² at 1.23 V_RHE, which is 2.4 times higher than bare photoanode (1.04 mA cm⁻²), with operational stability up to 100 h. Kinetic measurements indicate that pGO can promote charge transfer from TiFeO to the Co cubane catalyst. In contrast, SnO_x reduces charge recombination at the interface between TiFeO and the fluorinated tin oxide substrate. In-situ infrared spectroscopy shows the formation of an O−O bonded intermediate during water oxidation. This study highlights the crucial role of incorporating dual charge-transfer mediators into photoelectrodes for efficient solar energy conversion.

Photoredox dual reaction of organic synthesis and H₂ evolution opens up a novel pathway for collaboratively generating clean fuels and high-quality chemicals, providing a more effective approach of solar energy conversion. Herein, a surface defect-engineered ZnCoS/ZnCdS heterostructure with zinc blende (ZB)/wurtzite (WZ) phase junctions is synthesized for photocatalytic cooperative coupling of benzaldehyde (BAD) and H₂ production. This surface defect-engineered ZnCoS/ZnCdS heterostructure elaborately integrates the mixed phase junction advantage of ZnCdS semiconductor and the cocatalytic function of ZnCoS possessing Zn (V_Zn-ZnCoS/ZnCdS) or S vacancies (V_S-ZnCoS/ZnCdS). The optimum V_S-ZnCoS/ZnCdS simultaneously exhibits a superior H₂ production rate of 14.23 mmol h^-1 g^-1 accompanied with BAD formation rate of 12.29 mmol h^-1 g^-1 under visible-light irradiation, which is approximately two-fold greater than that of pristine ZnCdS. Under simulated sunlight irradiation (AM 1.5), V_S-ZnCoS/ZnCdS achieves H₂ evolution (27.43 mmol g_cat^-1 h^-1) with 0.52% of STH efficiency, accompany with 26.31 mmol g_cat^-1 h^-1 of BAD formation rate. The underlying solar-driven mechanism is elucidated by a series of in-situ characterization and control experiments, which reveals the synergistic effect of interfacial ZB/WZ phase junctions in ZnCdS and S vacancies of ZnCoS on enhancement of the photoredox dual reaction. The V_S-ZnCoS/ZnCdS follows a predominant oxygen-centered radical integrating with carbon-centered radical pathways for BAD formation and a simultaneous electron-driven proton reduction for H₂ production. Interestingly, the nature of surface vacancies not only facilitates the separation of photoinduced charge carriers but also able to selectively adjust the mechanism pathway for BAD production via tuning the oxygen-centered radical and carbon-centered radical formation.

Construction of iridium (Ir) based active sites on certain acid stable supports now is a general strategy for the development of low-Ir OER catalysts. Atomically doped Ir in the lattice of acid stable γ-MnO₂ has been recently achieved, which shows high activity and stability though Ir usage was reduced more than 95% than that in current commercial proton exchange membrane water electrolyzer (PEMWE). However, the activity and stability enhancement by Ir doping in γ-MnO₂ still remains elusive. Herein, high dispersion of iridium (up to 1.37 atom%) doping in the lattice of γ-MnO₂ has been achieved by optimizing the thermal decomposition of the iridium precursors. Benefiting from atomic dispersive doping of Ir, the optimized Ir-MnO₂ catalyst shows high OER activity, as it has turnover frequency of 0.655 s⁻¹ at an overpotential of 300 mV in 0.5 mol L^-1 H₂SO₄. The catalyst also shows high stability, as it can sustainably work at 100 mA cm^-2 for 24 h. Experimental and theoretical studies reveal that Ir is preferentially doped into β phase rather than R phase, and the Ir site is the active site for OER. The OER active site is postulated to be Ir⁵⁺-O(H)-Mn³⁺ unit structure on the surface. Furthermore, Ir doping changes the potential determining step from the formation of O* to the formation of *OOH, emphasizing the promoting effect toward OER derived from Ir sites. This work not only demonstrates the possibility of achieving atomic-level doping of Ir on the surface of a support to dramatically reduce Ir usage, but also, more importantly, reveals the mechanism behind accounting for the stability and activity enhancement by Ir doping. These important findings may serve as valuable guidance for further development of more efficient, stable and cost-effective low Ir-based OER catalysts for PEMWE.

Hydrogen peroxide (H₂O₂), an environmentally friendly chemical with high value, is extensively used in industrial production and daily life. However, the traditional anthraquinone method for H₂O₂ production is associated with a highly energy-consuming and heavily polluting process. Solor-driven photocatalytic evolution of H₂O₂ is a promising, eco-friendly, and energy-efficient strategy that holds great potential to substitute the traditional approach. Here, a ternary photocatalyst, NiS/CdS/Halloysite nanotubes (NiS/CdS/HNTs) is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst. The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations. HNTs serve as the carrier, which allows CdS to be uniformly dispersed onto its surface as small particles, increasing effective contact with H₂O and O₂ for H₂O₂ formation. Simultaneously, it resulted in the formation of a Schottky junction between NiS and CdS, which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons. Consequently, the optimized NiS/CdS/HNTs composite demonstrates an H₂O₂ evolution rate of 380.5 μmol·g^-1·h^-1 without adding any sacrificial agent or extra O₂, nearly 5.0 times that of pure CdS. This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.

The rational configuration of built-in electric field (IEF) in heterogeneous materials can significantly optimize the band structure to accelerate the separation of photogenerated charge carriers. However, the strength modulation of IEF formed by various materials has an uncertain enhancing effect on the separation of photogenerated carriers. Herein, a mesoporous MIL-125(Ti)@BiOCl S-scheme heterojunction with controllable IEF is prepared by green photoreduction reaction to investigate the relationship between IEF, microstructure, and photocatalytic activity. Moreover, the corresponding results demonstrate the MIL-125(Ti)@BiOCl effectively regulates the IEF strength through controlling the concentration of ligand defects, thereby optimizing the band structure and improving the efficiency of photogenerated charge separation. The optimized IEF significantly enhances the photocatalytic degradation performance of mesoporous MIL-125(Ti)-3@BiOCl towards tetracycline, with a k value of 0.07 min⁻¹, which are approximately 5.5 and 4.7 times greater than that of BiOCl (0.0127 min⁻¹) and MIL-125(Ti)-3 (0.015 min⁻¹). These findings provide a new pathway for regulating IEF within MOF-based heterojunctions, and offer new insights into the intrinsic correlations between defect structure, IEF, and photocatalytic activity.

Enzyme catalysis is a promising way to produce chiral products in a green and sustainable way. However, the high cost of cofactors and their relatively low recycling efficiency hinder the widespread application of enzyme catalysis in industry. In contrast, cofactor regeneration and recycling in cells is highly efficient, mainly due to physical effects caused by the ordered spatial organization of enzymes in vivo. The construction of similar catalytic systems with high cofactor recycling in vitro remains challenging. Here, we present a facile method to generate dual enzyme condensates in vitro based on intrinsically disordered region-mediated liquid-liquid phase separation. Typically, a carbonyl reductase from Serratia marcescens (SmCR_V4) and a glucose dehydrogenase from Bacillus megaterium (BmGDH) were co-localized in the condensates. This resulted in an up to 20-fold increase in cofactor recycling efficiency (substrate converted per cofactor per unit time), and a 3.4-fold increase in space-time yield compared to the free enzyme system. The reaction enhancement was shown to be highly correlated with the degree of condensation of the dual enzymes. Fluorescence confocal microscopy showed that the cofactor, nicotinamide adenine dinucleotide phosphate (NADPH), was enriched between neighboring enzymes during the reaction due to the proximity effect, facilitating its regeneration and recycling within the condensate. In a scaled-up synthesis, the consumption of NADPH was reduced 50-fold compared to industrial biocatalytic standards, while the condensate still maintained efficient product synthesis. Concentrating multiple enzymes in a nano- and micro-condensate to increase the reaction rate may provide a general and inexpensive method for improving cofactor-involved enzymatic reactions.

High density polyethylene (HDPE) pyrolysis and in-line oxidative steam reforming was carried out in a two-step reaction system consisting of a conical spouted bed reactor and a fluidized bed reactor. Continuous plastic pyrolysis was conducted at 550 °C and the volatiles formed were fed in-line to the oxidative steam reforming step (space-time 3.12 g_cat min g_HDPE^-1; ER = 0.2 and steam/plastic = 3) operating at 700 °C. The influence Ni based reforming catalyst support (Al₂O₃, ZrO₂, SiO₂) and promoter (CeO₂, La₂O₃) have on HDPE pyrolysis volatiles conversion and H₂ production was assessed. The catalysts were prepared by the wet impregnation and they were characterized by means of N₂ adsorption-desorption, X-ray fluorescence, temperature-programmed reduction and X-ray powder diffraction. A preliminary study on coke deposition and the deterioration of catalysts properties was carried out, by analyzing the tested catalysts through temperature programmed oxidation of coke, transmission electron microscopy, and N₂ adsorption-desorption. Among the supports tested, ZrO₂ showed the best performance, attaining conversion and H₂ production values of 92.2% and 12.8 wt%, respectively. Concerning promoted catalysts, they led to similar conversion values (around 90%), but significant differences were observed in H₂ production. Thus, higher H₂ productions were obtained on the Ni/La₂O₃-Al₂O₃ catalyst (12.1 wt%) than on CeO₂ promoted catalysts due to La₂O₃ capability for enhancing water adsorption on the catalyst surface.

Interface chemical modulation strategies are considered as promising method to prepare electrocatalysts for the urea oxidation reaction (UOR). However, conventional interface catalysts are generally limited by the inherent activity and incompatibility of the individual components themselves, and the irregular charge distribution and slow charge transfer ability between interfaces severely limit the activity of UOR. Therefore, we optimized and designed a Ni₂P/CoP interface with modulated surface charge distribution and directed charge transfer to promote UOR activity. Density functional theorycalculations first predict a regular charge transfer from CoP to Ni₂P, which creates a built-in electric field between Ni₂P and CoP interface. Optimization of the adsorption/desorption process of UOR/HER reaction intermediates leads to the improvement of catalytic activity. Electrochemical impedance spectroscopy and ex situ X-ray photoelectron spectroscopy characterization confirm the unique mechanism of facilitated reaction at the Ni₂P/CoP interface. Electrochemical tests further validated the prediction with excellent UOR/HER activities of 1.28 V and 19.7 mV vs. RHE, at 10 mA cm^-2, respectively. Furthermore, Ni₂P/CoP achieves industrial-grade current densities (500 mA cm^-2) at 1.75 V and 1.87 V in the overall urea electrolyzer (UOR||HER) and overall human urine electrolyzer (HUOR||HER), respectively, and demonstrates considerable durability.

In contrast to the predominant mono or difunctionalization of alkenes, the multi-site functionalization of alkenes involving the synergistic formation of more than two new C−C or C−X bonds is much challenging, especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission (AIE) property has been rarely reported. In present work, the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C-C bonds and C=O bond. A proposed reaction sequence involving C-H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations. Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration, which generated the desired twisted intramolecular charge transfer (TICT) AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends. The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens.

Selective reduction of N₂O by CO under excess O₂ was effectively catalyzed by Fe(0.9 wt%)-exchanged β zeolite (Fe0.9β) in the temperature range of 250-500 °C. Kinetic experiments showed that the apparent activation energy for N₂O reduction with CO was lower than that for the direct N₂O decomposition, and the rate of N₂O reduction with CO at 300 °C was 16 times higher than that for direct N₂O decomposition. Reaction order analyses showed that CO and N₂O were involved in the kinetically important step, while O₂ was not involved in the important step. At 300 °C, the rate of CO oxidation with 0.1% N₂O was two times higher than that of CO oxidation with 10% O₂. This quantitatively demonstrates the preferential oxidation of CO by N₂O under excess O₂ over Fe0.9β. Operando/in-situ diffuse reflectance ultraviolet-visible spectroscopy showed a redox-based catalytic cycle; α-Fe-O species are reduced by CO to give CO₂ and reduced Fe species, which are then re-oxidized by N₂O to regenerate the α-Fe-O species. The initial rate for the regeneration of α-Fe-O species under 0.1% N₂O was four times higher than that under 10% O₂. This result shows quantitative evidence on the higher reactivity of N₂O than O₂ for the regeneration of α-Fe-O intermediates, providing a fundamental reason why the Fe0.9β catalyst selectively promotes the CO + N₂O reaction under excess O₂ rather than the undesired side reaction of CO + O₂. The mechanistic model was verified by the results of in-situ Fe K-edge X-ray absorption spectroscopy.

A thoroughly mechanistic understanding of the electrochemical CO reduction reaction (eCORR) at the interface is significant for guiding the design of high-performance electrocatalysts. However, unintentionally ignored factors or unreasonable settings during mechanism simulations will result in false positive results between theory and experiment. Herein, we computationally identified the dynamic site preference change of CO adsorption with potentials on Cu(100), which was a previously unnoticed factor but significant to potential-dependent mechanistic studies. Combined with the different lateral interactions among adsorbates, we proposed a new C−C coupling mechanism on Cu(100), better explaining the product distribution at different potentials in experimental eCORR. At low potentials (from −0.4 to −0.6 V_RHE), the CO forms dominant adsorption on the bridge site, which couples with another attractively aggregated CO to form a C−C bond. At medium potentials (from −0.6 to −0.8 V_RHE), the hollow-bound CO becomes dominant but tends to isolate with another adsorbate due to the repulsion, thereby blocking the coupling process. At high potentials (above −0.8 V_RHE), the CHO intermediate is produced from the electroreduction of hollow-CO and favors the attraction with another bridge-CO to trigger C−C coupling, making CHO the major common intermediate for C−C bond formation and methane production. We anticipate that our computationally identified dynamic change in site preference of adsorbates with potentials will bring new opportunities for a better understanding of the potential-dependent electrochemical processes.

To address the high cost and limited electrochemical endurance of Pt-based electrocatalysts, the appropriate introduction of transition metal-based compounds as supports to disperse and anchor Pt species offers a promising approach for improving catalytic efficiency. In this study, sub-1 nm Pt nanoclusters were uniformly confined on NiO supports with a hierarchical nanotube/nanosheet structure (Pt/NiO/NF) through a combination of spatial domain confinement and annealing. The resulting catalyst exhibited excellent electrocatalytic activity and stability for hydrogen evolution (HER) and urea oxidation reactions (UOR) under alkaline conditions. Structural characterization and density functional theory calculations demonstrated that sub-1 nm Pt nanoclusters were immobilized on the NiO supports by Pt-O-Ni bonds at the interface. The strong metal-support interaction induced massive charge redistribution around the heterointerface, leading to the formation of multiple active sites. The Pt/NiO/NF catalyst only required an overpotential of 12 and 136 mV to actuate current densities of 10 and 100 mA cm^-2 for the HER, respectively, and maintained a voltage retention of 96% for 260 h of continuous operation at a current density of 500 mA cm^-2. Notably, in energy-efficient hydrogen production systems coupled with the HER and UOR, the catalyst required cell voltages of 1.37 and 1.53 V to drive current densities of 10 and 50 mA cm^-2, respectively—approximately 300 mV lower than conventional water electrolysis systems. This study presents a novel pathway for designing highly efficient and robust sub-nanometer metal cluster catalysts.

Artificial photosynthesis of hydrogen peroxide (H₂O₂) using covalent organic frameworks (COFs) as photocatalysts holds promise for future applications. However, the influence of linkage chemistry on the photoelectrochemical properties and photocatalytic performance of COFs remains a significant challenge. Herein, we designed and synthesized a model system with different linkages, including imine-, amine-, azo-linked COFs, then investigated their photocatalytic activity of overall H₂O₂ production. The photocatalytic results revealed varying activities for H₂O₂ synthesis among these COFs, with the azo-linked TTA-Azo-COF (COF synthesized by 4,4',4''-(1,3,5-triazine-2,4,6-triyl)-trianiline and terephthalaldehyde) demonstrating the highest overall H₂O₂ photosynthesis activity of 2516 μmol g⁻¹ h⁻¹ in an O₂ atmosphere without any sacrificial agents, which is 6.72 and 2.85 times higher than that of imine-linked TTA-COF and amine-linked TTA-COF-AR, respectively. Furthermore, TTA-Azo-COF maintained a high photosynthesis H₂O₂ activity of 2116 μmol g⁻¹ h⁻¹ under an air atmosphere, outperforming most COF-based photocatalytic systems under similar reaction conditions. Further characterizations and density functional theory calculations reveal these various linkages in different COFs result in distinct visible-light absorption, charge transfer capacities and formation energy barriers of key intermediates. This work revealed the significant impact of linkages on COFs and provided comprehensive guidance for the rational design of COFs with tailored linkages to fulfill specific requirements for future applications.

An efficient and novel approach is proposed for oxidative arylation of bio-based furfuryl alcohol (FA) to aryl furans (AFs), a versatile monomer of photoelectric materials, in the presence of UiO-67-Pd(F) with phenanthroline/ bipyridine, and poly-F substituted phenyl ligands as the mixture linkers. The results of control experiments and theoretical calculations reveal that the −F on the phenyl linkers efficiently tunes the electron-deficient nature of Pd through the Zr₆ clusters bridges, which favors the adsorption and activation of the furan ring. Furthermore, the conjugation of different nitrogen-containing ligands facilitates Pd coordination for the Heck-type insertion and subsequent electrophilic palladation, respectively. As a result, the oxidative arylation of FA derivatives is substantially enhanced because of these electronic and steric synergistic effects. Under the optimized conditions, 72.2% FA conversion and 74.8% mono aryl furan (MAF) selectivity are shown in the Heck-type insertion. Meanwhile, 85.3% of MAF is converted, affording 74.8% selectivity of final product (AFs) in the subsequent electrophilic palladation reaction. This process efficiency is remarkably higher than that with homogeneous catalysts. In addition, furan-benzene polymer obtained from the halogen-free synthesis catalyzed by UiO-67-Pd(F) show significantly better properties than that from conventional Suzuki coupling method. Therefore, the present work provides a new insight for useful AFs synthesis by oxidative arylation of bio-furan via rational tunning the metal center micro-environment of heterogeneous catalyst.

The electrochemical hydrogenation (ECH) of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) represents a pivotal pathway for the electrocatalytic upgrading of biomass-based organic small molecules, offering significant reductions in energy consumption while producing value-added chemicals. The conversion of HMF to DHMF is challenging due to the high reduction potential and complex intermediates of HMF ECH under neutral environment. Also, the total efficiency is hindered by sluggish anodic oxygen evolution reaction (OER) kinetics. Herein, we report a synthesis of highly alloyed Pd-Pt bimetallene (Pd₃Pt₁ BML) for HMF ECH coupled with formic acid oxidation reaction (FAOR). Through a combination of in-situ Raman spectroscopy, electron paramagnetic resonance analysis, and theoretical calculations, we elucidate that the HMF adsorption on Pd atoms, strategically separated by Pt atoms, is weakened compared to pure Pd surfaces. Additionally, Pt atoms serve as crucial providers of active hydrogen to neighboring Pd atoms, synergistically enhancing the reaction kinetics of HMF conversion with a Faradaic efficiency >93%. Meanwhile, the atomically dispersed Pt atoms endow Pd₃Pt₁ BML with high electrochemical performance for the direct pathway of FAOR at the anode. As a result, a FAOR-assisted HMF ECH system equipped with bifunctional Pd₃Pt₁ BML achieves the energy-efficient conversion of HMF to DHMF at electrolysis voltage of 0.72 V at 10 mA cm⁻². This work provides insights into the rational design of bifunctional catalysts featuring two distinct types of active sites for advanced energy electrocatalysis and ECH.

The accompanied forge of C(sp³)-S and C(sp³)-C(sp³) bonds across alkene frameworks serves as a potent strategy to construct biologically important compounds. Here, we report a metal-free, photochemically mediated fluoroalkyl-mono/disulfuration of unactivated alkenes with high efficiency and high selectivity. A wide range of terminal and internal alkenes are good coupling partners, affording the expected products in moderate to good yields (>90 examples). The exceedingly mild reaction conditions, exceptional functional group tolerance, broad substrate scope, and the potential for late-stage modifications of pharmaceutical molecules highlight the utility of this method in the preparation of privileged motifs from readily available disulfides, tetrasulfides, and diselenides. Mechanistic studies suggest that a secondary alkyl radical intermediate undergoes efficient homolytic substitution with disulfides, facilitating the modular synthesis of a diverse array of unsymmetrical thioethers.

Exploring platinum single-atom electrocatalysts (SACs) is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms. Herein, ruthenium clusters with several atoms (Ru_x) supported on nitrogen-doped, cost-efficient Black Pearls 2000 (Ru_xNBP), were synthesized as initial materials via a simple hydrothermal method. Then, [PtCl₄]^2‒ ion was reductively deposited on Ru_xNBP to obtain a Pt SAC (Pt₁/Ru_xNBP). Electrochemical measurements demonstrate the excellent HER performance of Pt₁/Ru_xNBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV. Moreover, the cell voltage of the proton exchange membrane electrolyzer with Pt₁/Ru_xNBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^‒2. Physical characterization and density functional theory calculations revealed that the preserved Pt-Cl bond of [PtCl₄]^2‒ and the Ru_xNBP support co-regulate the 5dstate of isolated Pt atoms and enhance the catalytic HER capacity of Pt₁/Ru_xNBP.

Covalent organic frameworks (COFs) based photocatalysts utilizing infrared light remains unexplored due to the limitation of electronic absorption. Herein, two novel two-dimensional (2D) polyimide-linked phthalocyanine COFs, namely MPc-DPA-COFs (M = Zn/Cu), were prepared from the imidization reaction of metal tetraanhydrides of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato (M(TAPc)) with 9,10-diphenyl anthracene (DPA). Both COFs possess highly crystalline eclipsed AA stacking structure with neighboring layer distance of 0.33 nm on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy. Effective π-π interaction between phthalocyanine chromophores in neighboring layers of 2D COFs leads to significant bathochromic-shift of narrow Q band from 697 nm for M(TAPc) to the infrared light absorption range of 760-1000 nm for MPc-DPA-COFs according to solid UV-vis diffuse reflectance spectra. This endows them in particular ZnPc-DPA-COF with excellent reactive oxygen species of ^•O₂⁻ and ¹O₂ generation activity under infrared light radiation (λ > 760 nm) based on the electron spin resonance spectroscopy measurement, in turn resulting in the excellent photocatalytic capacity towards oxidation of sulfides under infrared light radiation. Corresponding quenching experiments reveal the contribution of both ^•O₂⁻ and ¹O₂ to the oxidation of sulfides, but the former ^•O₂⁻ species plays a leading role in this photocatalytic process. The present result not only provides a new efficient infrared light photocatalyst but also unveils the good potentials of phthalocyanine-based COFs in photocatalysis.

Oxygen evolution reaction (OER) is often regarded as a crucial bottleneck in the field of renewable energy storage and conversion. To further accelerate the sluggish kinetics of OER, a cation and anion modulation strategy is reported here, which has been proven to be effective in preparing highly active electrocatalyst. For example, the cobalt, sulfur, and phosphorus modulated nickel hydroxide (denoted as NiCoPSOH) only needs an overpotential of 232 mV to reach a current density of 20 mA cm⁻², demonstrating excellent OER performances. The cation and anion modulation facilitates the generation of high-valent Ni species, which would activate the lattice oxygen and switch the OER reaction pathway from conventional adsorbate evolution mechanism to lattice oxygen mechanism (LOM), as evidenced by the results of electrochemical measurements, Raman spectroscopy and differential electrochemical mass spectrometry. The LOM pathway of NiCoPSOH is further verified by the theoretical calculations, including the upshift of O 2p band center, the weakened Ni-O bond and the lowest energy barrier of rate-limiting step. Thus, the anion and cation modulated catalyst NiCoPSOH could effectively accelerate the sluggish OER kinetics. Our work provides a new insight into the cation and anion modulation, and broadens the possibility for the rational design of highly active electrocatalysts.

Supported metal catalysts are the backbone of heterogeneous catalysis, playing a crucial role in the modern chemical industry. Metal-support interactions (MSIs) are known important in determining the catalytic performance of supported metal catalysts. This is particularly true for single-atom catalysts (SACs) and pseudo-single-atom catalysts (pseudo-SACs), where all metal atoms are dispersed on, and interact directly with the support. Consequently, the MSI of SACs and pseudo-SACs are theoretically more sensitive to modulation compared to that of traditional nanoparticle catalysts. In this work, we experimentally demonstrated this hypothesis by an observed size-dependent MSI modulation. We fabricated CoFe₂O₄ supported Pt pseudo-SACs and nanoparticle catalysts, followed by a straightforward water treatment process. It was found that the covalent strong metal-support interaction (CMSI) in pseudo-SACs can be weakened, leading to a significant activity improvement in methane combustion reaction. This finding aligns with our recent observation of CoFe₂O₄ supported Pt SACs. By contrast, the MSI in Pt nanoparticle catalyst was barely affected by the water treatment, giving rise to almost unchanged catalytic performance. This work highlights the critical role of metal size in determining the MSI modulation, offering a novel strategy for tuning the catalytic performance of SACs and pseudo-SACs by fine-tuning their MSIs.

The production of renewable methanol (CH₃OH) via the photocatalytic hydrogenation of CO₂ is an ideal method to ameliorate energy shortages and mitigate CO₂ emissions: however, the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift (RWGS) reaction. Herein, we present a novel approach for the synthesis of CH₃OH via photocatalytic CO₂ hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy (O_V)-rich molybdenum dioxide (MoO₂), resulting in a remarkable selectivity of 43.78%. The active sites in the Au/MoO₂ catalyst are high-density Au-oxygen vacancies, which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation. This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO₂ to CH₃OH.

Emerging as lamellar materials, covalent triazine frameworks (CTFs) exhibited great potential for photocatalysis, but their photocatalytic performance is always hindered by the prone recombination of photogenerated carriers. To overcome this obstacle, a 1D/2D step-scheme (S-scheme) heterojunction is constructed for photocatalytic synthesis of H₂O₂. The S-scheme heterojunction fabricated with CTF and ZnO effectively enhances light absorption, redox capabilities, and charge carrier separation and transfer. In particular, the CTF is decorated with benzothiadiazole and triazine groups as dual O₂ reduction active centers, boosting photocatalytic H₂O₂ production. The optimal ZC-10 hybrid delivers a maximum H₂O₂ generation rate of 12000 μmol g⁻¹ h⁻¹, 10.3 and 164 times higher than those of zinc oxide nanorods and CTFs, respectively. Moreover, the charge transfer mechanism in the S-scheme heterojunction is well investigated with in situ spectroscopic measurements and theoretical calculations.