Photothermal Effect- and Interfacial Chemical Bond-Modulated NiO_x/Ta₃N₅ Heterojunction for Efficient CO₂ Photoreduction

Abstract

Photothermal catalysis, which combines light promotion and thermal activation, is a promising approach for converting CO 2 into fuels. However, the development of photothermal catalysts with effective light-to-heat conversion, strong charge transfer ability, and suitable active sites remains a challenge. Herein, the photothermal effect-and interfacial N−Ni/ Ta−O bond-modulated heterostructure composed of oxygen vacancy-rich NiO x and Ta 3 N 5 was rationally fabricated for efficient photothermal catalytic CO 2 reduction. Beyond the charge separation capability conferred by the NiO x /Ta 3 N 5 heterojunction, we observed that the N−Ni and Ta−O bonds linking NiO x and Ta 3 N 5 form a spatial charge transfer channel, which enhances the interfacial electron transfer. Additionally, the presence of surface oxygen vacancies in NiO x induced nonradiative relaxation, resulting in a pronounced photothermal effect that locally heated the catalyst and accelerated the reaction kinetically. Leveraging these favorable factors, the NiO x /Ta 3 N 5 hybrids exhibit remarkably elevated activity (≈32.3 μmol•g −1 •h −1 ) in the conversion of CO 2 to CH 4 with near-unity selectivity, surpassing the performance of bare Ta 3 N 5 by over 14 times. This study unveils the synergistic effect of photothermal and interfacial chemical bonds in the photothermal−photocatalytic heterojunction system, offering a novel approach to enhance the reaction kinetics of various catalysts.