Photoelectrochemical (PEC) water splitting offers one of the most promising solutions for sustainable solar-to-chemical fuel conversion. However, sluggish charge migration across the photoelectrode interface fundamentally limits the PEC efficiency. Herein, we design and engineer an atomic-scale interfacial charge conduit by inserting metal nanoclusters between the cocatalyst and semiconductor. The distinct work-function differences among the cocatalyst, metal nanoclusters, and semiconductor induce interfacial band bending, enabling the selective, directional transport of photogenerated carriers from the semiconductor to the cocatalyst. Particularly, bismuth (Bi) nanoclusters synthesized through a universal laser-induced in situ growth strategy on 29 distinct bismuth-based semiconductors induce the formation of metal/semiconductor Schottky junctions and directionally steer electron migration into the semiconductor conduction band while effectively suppressing electron–hole recombination. Benefiting from the Bi nanoclusters and CoFe cocatalyst, the large-area (3 × 3 cm²) earth-abundant CoFe/Bi/BiVO₄ photoanode achieves a photocurrent of 26 mA at 1.1 V versus RHE, maintaining stable performance for 600 h. For practical application, an all-oxide-semiconductor tandem PEC device combining a CoFe/Bi/BiVO₄ photoanode and a Pt/TiO₂/Ga₂O₃/Cu₂O/CuO photocathode records an unassisted 4.8% solar-to-hydrogen conversion efficiency under AM 1.5G light illumination for 70 h. This work demonstrates the atomic-scale engineering of interfacial charge conduits for high-efficiency solar energy conversion.

Metal (hydro)oxides are among the most effective heterogeneous water oxidation catalysts. Elucidating the interactions between oxygen-bridged metal sites at a molecular level is essential for developing high-performing electrocatalysts. Here we demonstrate that adjacent metal-hydroxyl groups function as intramolecular proton–electron transfer relays to enhance water oxidation kinetics. We achieved this using a well-defined molecular platform with an aza-fused π-conjugated microporous polymer that coordinates molecular Ni or Ni–Fe sites that emulate the structure of the most active edge sites in Ni–Fe materials for studying the heterogeneous water oxidation mechanism. We combine experimental and computational results to reveal the origin of pH-dependent reaction kinetics for O–O bond formation. We find both the anions in solution and the adjacent Ni3+–OH site act as proton transfer relays, facilitating O–O bond formation and leading to pH-dependent water oxidation kinetics. This study provides significant insights into the critical role of electrolyte pH in water oxidation electrocatalysis and enhancement of water oxidation activity in Ni–Fe systems. (Figure presented.)

Electrochemical CO₂ reduction provides a promising strategy to synthesize C₂₊ compounds with reduced carbon intensity; however, high overall energy consumption restricts practical implementation. Using acidic media enables high CO₂ utilization and low liquid product crossover, but to date has suffered low C₂₊ product selectivity. Here we hypothesize that adjacent pairs of atomic-copper active sites may favour C–C coupling, thus facilitating C₂₊ product formation. We construct tandem electrocatalysts with two distinct classes of active sites, the first for CO₂ to CO, and the second, a dual-atomic-site catalyst, for CO to C₂₊. This leads to an ethanol Faradaic efficiency of 46% and a C₂₊ product Faradaic efficiency of 91% at 150 mA cm⁻² in an acidic CO₂ reduction reaction. We document a CO₂ single-pass utilization of 78% and an energy efficiency of 30% towards C₂₊ products; an ethanol crossover rate of 5%; and an ethanol product concentration of 4.5%, resulting in an exceptionally low projected energy cost of 249 GJ t−1 for the electrosynthesis of ethanol via the CO₂ reduction reaction.

Ultrafast relaxation dynamics of 13,14-diphenyldibenzo[b,j][4,7]phenanthroline (DBP3) thin film were studied with various time-resolved spectroscopic techniques including TCSPC, fluorescence up-conversion and fs transient absorption spectroscopy. Two fluorescence emission bands originating from S<inf>1</inf> state of phenanthroline and intramolecular benzene excimer were observed. Intramolecular benzene excimer fluorescence lifetime is suppressed by a factor of ten in thin film as compared to diluted solution while conversely the S<inf>1</inf> fluorescence lifetime of DBP3 is enhanced in film.

Developing high-activity and long-term stable electrocatalysts for electrochemical CO2 reduction reaction (eCO₂RR) to valuable products is still a challenge. An in-depth understanding of reaction mechanisms and the structure-function relationship is required for the development of an advanced catalytic eCO₂RR system. Herein, a coordination polymer of indium(III) and benzenehexathiol (BHT) was developed as an electrocatalyst (In-BHT) for eCO₂RR to HCOO⁻, which displayed an outstanding catalytic performance over the entire pH range. However, experimental results revealed significantly different catalytic pathways in the acid and neutral/alkaline solutions, which are attributed to the influence of redox non-innocent ligands on the rate-determining step (RDS). In the acid solution, the RDS is the formation of *OCOH intermediate through the proton transfer that originates from H₂O in the solution, leading to relatively sluggish kinetics. But in the neutral or alkaline solution, the thiolate groups could be protonated during the catalytic process, and such proton can attack on carbon of absorbed CO₂ via an intramolecular proton transfer, promoting the formation of *OCHO intermediate, resulting in faster kinetics. Our findings revealed the pivotal roles of the redox non-innocent ligands of metal active sites for eCO₂RR, providing a new idea for designing highly efficient electrocatalysts.

Significant efforts have been dedicated to the development of highly efficient electrocatalysts for electrochemical CO₂ reduction reactions (eCO₂RR). The outer coordination spheres of catalytic centers may play a pivotal role in the reaction pathway and kinetics for eCO₂RR. Herein, three single copper sites coordinated Aza-fused conjugated organic frameworks (Aza-COFs-Cu) with different outer coordination spheres around Cu sites are designed. Experiment and density functional theory (DFT) calculation results reveal that the redox non-innocent outer spheres around Cu sites significantly influence the catalytic performance of Aza-COFs-Cu for eCO₂RR. When adjacent redox non-innocent groups of uncoordinated aromatic-N and quinone around the Cu centers act as the symmetry-breaking sites, the energy-consuming activation process of CO₂ molecules can be accelerated via the H+/e− transfer process to form *COOH intermediates, which will significantly improve the performance for eCO₂RR. This study provides a new perspective on the design of more advanced electrocatalysts for eCO2RR through redox non-innocent spheres engineering.

In artificial photosynthesis, molecule/semiconductor hybrids combine the merits of the high activity of molecular catalysts and the high stability of semiconductor light absorbers. We report here a host-guest strategy for hybrid photoanode fabrication, where phosphonate-derivatized cyclodextrins (p-CDs) as hosts were anchored on the surface of a tungsten oxide (WO₃) film, and molecular catalysts as guests were self-encapsulated into the cavities of p-CDs in either aqueous or organic media. By choosing an admantanyl cobaloxime complex (Co1) as a molecular water oxidation catalyst, the resulting WO₃|p-CD|Co1 photoanode exhibited high photoelectrochemical (PEC) activity and stability for water oxidation due to the unexpected efficient charge separation and the strong affinity between p-CD and catalyst. In addition, the WO₃|p-CD was identified to be a versatile platform for catalyst loading, when a 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) derivative was employed as the guest molecule, the conversion yield of PEC alcohol oxidation to aldehyde was dramatically increased.

Amorphous catalysts behave differently in oxygen evolution reaction (OER) performance compared with their crystalline counterparts; however, the origin of this disparity is still ambiguous. Herein, amorphous and crystalline CoOOH are invoked as the model catalysts to explore the origin of their difference in the OER performance. Electrochemical measurement results demonstrate that the amorphous CoOOH has more active sites in quantity but lower intrinsic activity per site than the crystalline CoOOH in the initial stage of the OER. Nevertheless, the intrinsic activity per site of the amorphous CoOOH continues to increase until a level close to that of the crystalline CoOOH is achieved when the OER proceeds. On the basis of operando characterizations and electrochemical analysis, a dual-pathway model of reconstruction is proposed to explain the catalytic behaviors of these CoOOH. The intrinsic activity of catalysts is dominated by two reconstruction pathways. The distinction of intrinsic activity between the amorphous and crystalline CoOOH is caused by the different proportions of each pathway included in OER. Moreover, the quenching reaction between Co4+ and the oxygen vacancy in the amorphous catalyst motivates the surface reconstruction and subsequently promotes the crystallinity. This study provides a perspective for understanding the surface reconstruction mechanism in the OER.

Photoelectrochemical (PEC) oxidation of organics to value-added chemicals presents a sustainable alternative to conventional anodic oxygen evolution reactions. While significant progress has been made in PEC organic transformations, asymmetric PEC organic conversions remain underexplored. In this study, we report the chloride-mediated PEC enantioselective epoxidation of alkenes at a mesoporous BiVO4photoanode in a CH2Cl2/aqueous NaCl biphasic system using water as an oxygen source. The NaCl electrolyte serves as a redox mediator and chlorine precursor, where photo-oxidation generates reactive chlorine species (Cl2/HClO) that migrate into the organic phase to enable asymmetric catalysis via chiral Mn-salen catalysts. Spectroelectrochemical analysis verified the photogenerated MnV═O species as the key intermediate. A key innovation of this study lies in the use of a pendant alkyl chain-modified pyridine N-oxide additive, which uniquely stabilizes the MnV═O intermediate through axial coordination while simultaneously acting as a phase-transfer catalyst to facilitate hypochlorous acid migration, dramatically boosting the epoxidation efficiency. This approach achieves high yields (up to 95%) and enantioselectivities (up to 88% enantiomeric excess), even in a challenging artificial seawater/CH2Cl2biphasic system. By utilizing water as a green oxygen source and coupling with solar fuel production, this work presents a practical and efficient route for asymmetric PEC synthesis.

Regulating the spintronic structure of electrocatalysts can improve the oxygen evolution reaction performance efficiently. Nonetheless, the effects of tuning the spintronic structure for the oxygen evolution reaction mechanisms have rarely been discussed. Here, we show a ruthenium-cobalt-tin oxide with optimized spintronic structure due to the quantum spin interaction of Ru and Co. The specific spintronic structure of ruthenium-cobalt-tin oxide promotes the charge transfer kinetics and intermediates evolution behavior under applied potential, generating long-lived active species with higher spin density sites for the oxygen evolution reaction after the reconstruction process. Moreover, the ruthenium-cobalt-tin oxide possesses decoupled proton-electron transfer procedure during the oxygen evolution reaction process, demonstrating that the electron transfer procedure of O-O bond formation between *O intermediate and lattice oxygen in Co-O-Ru is the rate-determining step of the oxygen evolution reaction process. This work provides rational perspectives on the correlation between spintronic structure and oxygen evolution reaction mechanism.