Boosting photo-thermal co-catalysis CO2 methanation by tuning interface electron transfer via Mott-Schottky heterojunction effect.

Herein, a Mott-Schottky heterojunction catalyst was developed by incorporating nickel (Ni) nanometallic particles supported on nitrogen-doped carbon-coated TiO 2 , enabling full-spectrum light absorption and facilitating a robust metal-support interface. This catalyst demonstrated exceptional performance in photo-thermal catalysis. Specifically, the Ni/0.5-TiO 2 @NC catalyst achieved a CO 2 hydrogenation rate of 65.3 mmol/(g cat ·h) with a CH 4 selectivity exceeding 99% under full-spectrum illumination. Remarkably, the catalyst exhibited excellent stability, maintaining its performance over two reaction cycles. The strong metal-support interface of the Mott-Schottky heterojunction catalyst enhanced photo-generated electron-hole separation efficiencies, leading to a substantial rise in catalyst surface temperature. Consequently, this phenomenon accelerated the reaction kinetics and lowered the activation energy, thereby improving overall efficiency. [Display omitted] • Mott-Schottky heterojunctions consisting of TiO 2 @NC-support and highly dispersed Ni NPs catalysts were successfully prepared. • The Mott-Schottky heterojunction catalysts exhibit rapid interface electron transfer, leading to superb carrier separation efficiencies. • The Ni/0.5-TiO 2 @NC catalyst demonstrates exceptional photo-thermal co-catalytic effects, resulting in outstanding performance in the RWGS reaction. • The in-situ DRIFTS analysis revealed that the mechanism governing the photo-thermal co-catalytic RWGS reaction follows the *HCOO pathway. Photo-thermal co-catalytic reduction of CO 2 to synthesize value-added chemicals presents a promising approach to addressing environmental issues. Nevertheless, traditional catalysts exhibit low light utilization efficiency, leading to the generation of a reduced number of electron-hole pairs and rapid recombination, thereby limiting catalytic performance enhancement. Herein, a Mott-Schottky heterojunction catalyst was developed by incorporating nitrogen-doped carbon coated TiO 2 supported nickel (Ni) nanometallic particles (Ni/x-TiO 2 @NC). The optimal Ni/0.5-TiO 2 @NC sample displayed a conversion rate of 71.6 % and a methane (CH 4) production rate of 65.3 mmol/(g cat ·h) during photo-thermal co-catalytic CO 2 methanation under full-spectrum illumination, with a CH 4 selectivity exceeding 99.6 %. The catalyst demonstrates good stability as it shows no decay after two reaction cycles. The Mott-Schottky heterojunction catalysts display excellent efficiency in separating photo-generated electron-hole pairs and elevate the catalysts' temperature, thus accelerating the reaction rate. The in-situ experiments revealed that light-induced electron transfer effectively facilitates H 2 dissociation and enhances surface defects, thereby promoting CO 2 adsorption. This study introduces a novel approach for developing photo-thermal catalysts for CO 2 reduction, aiming to enhance solar energy utilization and facilitate interface electron transfer. [ABSTRACT FROM AUTHOR]