Zr-Induced Self-Alloying Enables 96% Methanol Selectivity in Photothermal CO 2 Reduction over Cu-In 2 O 3 Catalysts

Plasmonic metal-modified indium oxide (In 2 O 3 ) catalysts exhibiting localized surface plasmon resonance (LSPR) effects have emerged as platforms for photothermal carbon dioxide (CO 2 ) reduction. However, their practical application is hindered by low methanol selectivity, primarily arising from the competing reverse water−gas shift (RWGS) reaction. To address this limitation, we report a Zr-doped Cu-In 2 O 3 catalyst (denoted as CuIn-InZrO x ) for photothermal CO 2 hydrogenation to methanol (CHM). Systematic characterization studies demonstrate that Zr doping induced in situ alloying between Cu and In, establishing a Zr-induced self-alloying strategy. Under photothermal conditions, the CuIn-InZrO x catalyst achieved a methanol generation rate of 2174 μmol g −1 h −1 (at the millimolar scale) and a methanol selectivity of 96% (exceeding the industrial benchmark of >90%). The CuIn alloy preserved strong LSPR properties, which enhanced CO 2 adsorption and activation. Combined in situ spectroscopic and theoretical investigations confirm that Zr incorporation favored methanol formation through the formate pathway, suppressing the RWGS reaction and facilitating product desorption. This self-alloying strategy provides an approach to improving methanol selectivity without compromising catalytic activity for In 2 O 3 -based photothermal catalysts.