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Solar-powered photosynthesis though two-electron oxygen reduction presents an eco-friendly and energy-efficient approach for producing high-value H2O2. However, achieving highly efficient photosynthesis for H2O2 generation is challenging due to limited photogenerated charge transfer efficiency and the sluggish kinetic process. Herein, we use a defect engineering approach that involves creating N vacancies around Zn–N4 to modify the electron density of Zn single atoms for efficient H2O2 production. The presence of adjacent N vacancies increases the electron density of Zn–N4 sites and makes the *H2O2 desorption step that generates H2O2 (*H2O2 → H2O2) thermodynamically more favorable. The separation and migration of photogenerated electron–hole pairs is also greatly promoted. Under simulated sunlight, the H2O2 yield for Zn–N4 sites with adjacent N vacancies reaches 1363.4 μmol g−1 h−1, 3.2 times higher than that of CN, and the apparent quantum yield is 24.6% (λ = 350 nm). [ABSTRACT FROM AUTHOR]

MXenes have been garnering significant attention in diverse fields, such as energy storage, catalysis, sensing, and electromagnetic interference shielding. Recently, MXenes were predicted to exhibit excellent thermoelectric properties, and attempts have been conducted to fabricate relevant devices. Nevertheless, the complexity of the preparation process, low productivity, and susceptibility to oxidation have obstructed their full potential. In this study, we investigated the stability of undelaminated multilayers Mo2TiC2 and Mo2C under different conditions, which exhibited a much better thermal stability and oxidation resistance compared to their monolayer counterparts. Moreover, the thermoelectric properties of undelaminated multilayers Mo2TiC2 and Mo2C were studied, which revealed comparable TE performance to monolayer counterparts, with the economy, productivity and stability being greatly improved. Finally, block TE devices with 2 pairs of p/n-type multilayer MXene blocks were prepared in the form of a commercial TE module and generated an open-circuit voltage of 3.43 mV at a temperature difference of 25 K with the maximum output power of 22.68 nW. These results demonstrate a feasible and economical method to process MXene-based thermoelectric devices, opening a new avenue for both MXene and thermoelectric communities. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction into ideal hydrocarbon fuels, such as CH4, is a sluggish kinetic process involving adsorption of multiple intermediates and multi‐electron steps. Achieving high CH4 activity and selectivity therefore remains a great challenge, which largely depends on the efficiency of photogenerated charge separation and transfer as well as the intermediate energy levels in CO2 reduction. Herein, we construct La and Cu dual‐atom anchored carbon nitride (LaCu/CN), with La‐N4 and Cu‐N3 coordination bonds connected by Cu−N−La bridges. The asymmetric Cu−N−La species enables the establishment of an atomic‐level donor‐acceptor structure, which allows the migration of electrons from La atoms to the reactive Cu atom sites. Simultaneously, intermediates during CO2 reduction on LaCu/CN demonstrate thermodynamically more favorable process for CH4 formation based on theoretical calculations. Eventually, LaCu/CN exhibits a high selectivity (91.6 %) for CH4 formation with a yield of 125.8 μmol g−1, over ten times of that for pristine CN. This work presents a strategy for designing multi‐functional dual‐atom based photocatalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction into ideal hydrocarbon fuels, such as CH4, is a sluggish kinetic process involving adsorption of multiple intermediates and multi‐electron steps. Achieving high CH4 activity and selectivity therefore remains a great challenge, which largely depends on the efficiency of photogenerated charge separation and transfer as well as the intermediate energy levels in CO2 reduction. Herein, we construct La and Cu dual‐atom anchored carbon nitride (LaCu/CN), with La‐N4 and Cu‐N3 coordination bonds connected by Cu−N−La bridges. The asymmetric Cu−N−La species enables the establishment of an atomic‐level donor‐acceptor structure, which allows the migration of electrons from La atoms to the reactive Cu atom sites. Simultaneously, intermediates during CO2 reduction on LaCu/CN demonstrate thermodynamically more favorable process for CH4 formation based on theoretical calculations. Eventually, LaCu/CN exhibits a high selectivity (91.6 %) for CH4 formation with a yield of 125.8 μmol g−1, over ten times of that for pristine CN. This work presents a strategy for designing multi‐functional dual‐atom based photocatalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction into ideal hydrocarbon fuels, such as CH4, is a sluggish kinetic process involving adsorption of multiple intermediates and multi‐electron steps. Achieving high CH4 activity and selectivity therefore remains a great challenge, which largely depends on the efficiency of photogenerated charge separation and transfer as well as the intermediate energy levels in CO2 reduction. Herein, we construct La and Cu dual‐atom anchored carbon nitride (LaCu/CN), with La‐N4 and Cu‐N3 coordination bonds connected by Cu−N−La bridges. The asymmetric Cu−N−La species enables the establishment of an atomic‐level donor‐acceptor structure, which allows the migration of electrons from La atoms to the reactive Cu atom sites. Simultaneously, intermediates during CO2 reduction on LaCu/CN demonstrate thermodynamically more favorable process for CH4 formation based on theoretical calculations. Eventually, LaCu/CN exhibits a high selectivity (91.6 %) for CH4 formation with a yield of 125.8 μmol g−1, over ten times of that for pristine CN. This work presents a strategy for designing multi‐functional dual‐atom based photocatalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction into ideal hydrocarbon fuels, such as CH4, is a sluggish kinetic process involving adsorption of multiple intermediates and multi‐electron steps. Achieving high CH4 activity and selectivity therefore remains a great challenge, which largely depends on the efficiency of photogenerated charge separation and transfer as well as the intermediate energy levels in CO2 reduction. Herein, we construct La and Cu dual‐atom anchored carbon nitride (LaCu/CN), with La‐N4 and Cu‐N3 coordination bonds connected by Cu−N−La bridges. The asymmetric Cu−N−La species enables the establishment of an atomic‐level donor‐acceptor structure, which allows the migration of electrons from La atoms to the reactive Cu atom sites. Simultaneously, intermediates during CO2 reduction on LaCu/CN demonstrate thermodynamically more favorable process for CH4 formation based on theoretical calculations. Eventually, LaCu/CN exhibits a high selectivity (91.6 %) for CH4 formation with a yield of 125.8 μmol g−1, over ten times of that for pristine CN. This work presents a strategy for designing multi‐functional dual‐atom based photocatalysts. [ABSTRACT FROM AUTHOR]