Stable hydroxyl-anchored CuNi nanocatalysts from CuNiMgAl-LDH thermal reduction for efficient photothermal CO2 conversion

Cu-based nanocatalysts hold promise for the reverse water–gas shift (RWGS) reaction. However, irreversible sintering of the Cu catalyst for deactivation remains a persistent challenge under thermal or photothermal processes. In this study, we develop an anti-sintering catalyst using CuNiMgAl layered-double-hydroxide (LDH)-derived hydroxyl engineering to anchor ultrafine CuNi nanoparticles, achieving stable photothermal RWGS conversion. For Cu3Ni-MA, the oxyphilic Ni dopants facilitate the formation of hydroxyl-coordinated Cu2+–Ni2+ species during the calcination of LDH-derived materials; meanwhile, the Ni incorporation enhances the plasmonic effect of CuNi nanocatalysts to drive H2 spillover for hydroxyl replenishment under light irradiation, which is diverged from conventional Cu3Ni alloy-based catalysts. This Cu3Ni-MA achieves a CO production rate of 339.8 mmol g−1 h−1 with 98% selectivity, outperforming thermal catalysis by 3.5-fold in RWGS conversion. Notably, the catalyst exhibits robust photothermal CO2 hydrogenation stability, preserving >99% of its original activity and CO selectivity during 30 d of intermittent start–stop cycles and 280-h continuous testing. This study offers alternative perspectives for designing anti-sintering catalysts for photothermal catalytic systems by coupling dynamic hydroxyl regulation with plasmonic activation mechanisms. The irreversible sintering of Cu catalyst for deactivation remains a persistent challenge under thermal or photothermal reverse water-gas shift reaction process. Now, a hydroxyl-engineered CuNi nanocatalyst, derived from CuNiMgAl-LDH, achieves high and stable CO evolution under solar light by preventing sintering through dynamic hydroxyl anchoring of the nanoparticles.