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Photocatalytic conversion of CO2 and H2O into fuels and oxygen is a highly promising solution for carbon‐neutral recycling. Traditionally, researchers have studied CO2 reduction and H2O oxidation separately, overlooking potential synergistic interplay between these processes. This study introduces an innovative approach, spatial synergy, which encourages synergistic progress by bringing the two half‐reactions into atomic proximity. To facilitate this, we developed a defective ZnIn2S4‐supported single‐atom Cu catalyst (Cu−SA/D−ZIS), which demonstrates remarkable catalytic performance with CO2 reduction rates of 112.5 μmol g−1 h−1 and water oxidation rates of 52.3 μmol g−1 h−1, exhibiting a six‐fold enhancement over D−ZIS. The structural characterization results indicated that the trapping effect of vacancy associates on single‐atom copper led to the formation of an unsaturated coordination structure, Cu‐S3, consequently giving rise to the CuZn′VS⋅⋅VZn" defect complexes. FT‐IR studies coupled with theoretical calculations reveal the spatially synergistic CO2 reduction and water oxidation on CuZn′VS⋅⋅VZn", where the breakage of O−H in water oxidation is synchronized with the formation of *COOH, significantly lowering the energy barrier. Notably, this study introduces and, for the first time, substantiates the spatial synergy effect in CO2 reduction and H2O oxidation through a combination of experimental and theoretical analyses, providing a fresh insight in optimizing photocatalytic system. [ABSTRACT FROM AUTHOR]

High‐efficient photoelectrocatalytic direct ammonia oxidation reaction (AOR) conducted on semiconductor photoanodes remains a substantial challenge. Herein, we develop a strategy of simply introducing ppm levels of Cu ions (0.5–10 mg/L) into NH3 solutions to significantly improve the AOR photocurrent of bare BiVO4 photoanodes from 3.4 to 6.3 mA cm−2 at 1.23 VRHE, being close to the theoretical maximum photocurrent of BiVO4 (7.5 mA cm−2). The surface charge‐separation efficiency has reached 90 % under a low bias of 0.8 VRHE. This AOR exhibits a high Faradaic efficiency (FE) of 93.8 % with the water oxidation reaction (WOR) being greatly suppressed. N2 is the main AOR product with FEs of 71.1 % in aqueous solutions and FEs of 100 % in non‐aqueous solutions. Through mechanistic studies, we find that the formation of Cu−NH3 complexes possesses preferential adsorption on BiVO4 surfaces and efficiently competes with WOR. Meanwhile, the cooperation of BiVO4 surface effect and Cu‐induced coordination effect activates N−H bonds and accelerates the first rate‐limiting proton‐coupled electron transfer for AOR. This simple strategy is further extended to other photoanodes and electrocatalysts. [ABSTRACT FROM AUTHOR]

Herein, we fabricated a π–π stacking hybrid photocatalyst by combining two two‐dimensional (2D) materials: g‐C3N4 and a Cu‐porphyrin metal–organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO2 to CO and CH4 under the typical level (20 %) of O2 in the air. Intriguingly, the presence of O2 did not suppress CO2 reduction; instead, a fivefold increase compared with that in the absence of O2 was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D‐MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O2. Then the formed hydroxylated Cu node maintained its structure during aerobic CO2 reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O2. Theoretical calculations further demonstrated that CO2 reduction, instead of O2 reduction, occurred preferentially on the hydroxylated Cu node. [ABSTRACT FROM AUTHOR]

Prospects in light‐driven water activation have prompted rapid progress in hydrogenation reactions. We describe a Ni2+−N4 site built on carbon nitride for catalyzed semihydrogenation of alkynes, with water supplying protons, powered by visible‐light irradiation. Importantly, the photocatalytic approach developed here enabled access to diverse deuterated alkenes in D2O with excellent deuterium incorporation. Under visible‐light irradiation, evolution of a four‐coordinate Ni2+ species into a three‐coordinate Ni+ species was spectroscopically identified. In combination with theoretical calculations, the photo‐evolved Ni+ is posited as HO−Ni+−N2 with an uncoordinated, protonated pyridinic nitrogen, formed by coupled Ni2+ reduction and water dissociation. The paired Ni−N prompts hydrogen liberation from water, and it renders desorption of alkene preferred over further hydrogenation to alkane, ensuring excellent semihydrogenation selectivity. [ABSTRACT FROM AUTHOR]

The sluggish H2O oxidation kinetics on photoanodes severely obstructs the overall solar‐to‐energy efficiency of photoelectrochemical (PEC) cells. Herein, we find a 10 to 55‐fold increase of photocurrent by conducting ammonia oxidation reaction (AOR) on hematite (α‐Fe2O3) photoanodes under near‐neutral pH (9–11) and moderate applied potentials (1.0–1.4 VRHE) compared to H2O oxidation. By rate law analysis and operando spectroscopic studies, we confirm the non‐radical nucleophilic attack of NH3 molecules on high‐valent surface Fe−O species (e.g. FeIV=O) and Fe−N species that produces NOx− and N2, respectively, which overwhelms the nucleophilic attack of H2O on surface FeIV=O and contributes to a high Faradaic efficiency of above 80 % for AOR. This work reveals a novel non‐radical nucleophilic attack strategy, which is significantly different from the conventional indirect radical‐mediated AOR mechanism, for the rational design of high‐performance AOR photoelectrocatalysts. [ABSTRACT FROM AUTHOR]

Current plasmonic photocatalysts are mainly based on noble metal nanoparticles and rarely work in the infrared (IR) light range. Herein, cost‐effective Bi2O3−x with oxygen vacancies was formed in situ on commercial bismuth powder by calcination at 453.15 K in atmosphere. Interestingly, defects introduced into Bi2O3−x simultaneously induced a localized surface plasmon resonance (LSPR) in the wavelength range of 600–1400 nm and enhanced the adsorption for CO2 molecules, which enabled efficient photocatalysis of CO2‐to‐CO (ca. 100 % selectivity) even under low‐intensity near‐IR light irradiation. Significantly, the apparent quantum yield for CO evolution at 940 nm reached 0.113 %, which is approximately 4 times that found at 450 nm. We also showed that the unique LSPR allows for the realization of a nearly linear dependence of photocatalytic CO production rate on light intensity and operating temperature. Finally, based on an IR spectroscopy study, an oxygen‐vacancy induced Mars‐van Krevlen mechanism was proposed to understand the CO2 reduction reactions. [ABSTRACT FROM AUTHOR]

An efficient redox reaction between organic substrates in solution and photoinduced h+vb/e−cb on the surface of photocatalysts requires the substrates or solvent to be adsorbed onto the surface, and is consequentially marked by a normal kinetic solvent isotope effect (KSIE≥1). Reported herein is a universal inverse KSIE (0.6-0.8 at 298 K) for the reductive dehalogenation of aromatic halides which cannot adsorb onto TiO2 in a [D0]methanol/[D4]methanol solution. Combined with in situ ATR-FTIR spectroscopy investigations, a previously unknown pathway for the transformation of these aromatic halides in TiO2 photocatalysis was identified: a proton adduct intermediate, induced by released H+/D+ from solvent oxidation, accompanies a change in hybridization from sp2 to sp3 at a carbon atom of the aromatic halides. The protonation event leads these aromatic halides to adsorb onto the TiO2 surface and an ET reaction to form dehalogenated products follows. [ABSTRACT FROM AUTHOR]

Current plasmonic photocatalysts are mainly based on noble metal nanoparticles and rarely work in the infrared (IR) light range. Herein, cost‐effective Bi2O3−x with oxygen vacancies was formed in situ on commercial bismuth powder by calcination at 453.15 K in atmosphere. Interestingly, defects introduced into Bi2O3−x simultaneously induced a localized surface plasmon resonance (LSPR) in the wavelength range of 600–1400 nm and enhanced the adsorption for CO2 molecules, which enabled efficient photocatalysis of CO2‐to‐CO (ca. 100 % selectivity) even under low‐intensity near‐IR light irradiation. Significantly, the apparent quantum yield for CO evolution at 940 nm reached 0.113 %, which is approximately 4 times that found at 450 nm. We also showed that the unique LSPR allows for the realization of a nearly linear dependence of photocatalytic CO production rate on light intensity and operating temperature. Finally, based on an IR spectroscopy study, an oxygen‐vacancy induced Mars‐van Krevlen mechanism was proposed to understand the CO2 reduction reactions. [ABSTRACT FROM AUTHOR]