Construction of geopolymer zeolite-graphene/carbon nanotube interface for strong metal−support interaction (SMSI) effect to achieve efficient solar evaporation and highly selective synergistic catalytic reduction of CO₂

Abstract

The challenges of CO₂ energy conversion and the shortage of clean water resources have become critical global issues. Photocatalytic CO₂ reduction and solar-driven evaporation technology are promising solutions to address these challenges. In this study, a dual-functional biomimetic, mushroom-shaped 3D geopolymer zeolite-nickel@carbon nanotube-graphene composite material (3DGZ-Ni@CNTG) solar evaporator was developed, which integrates high photothermal evaporation with excellent CO₂ photocatalytic reduction performance. It precisely combines the zeolite water transport layer, carbon nanotube-graphene (CNTG) photothermal layer, and metallic nickel catalyst, with each component's functions working synergistically. Under 1-sun intensity, the evaporator achieves an evaporation efficiency of 151% and an evaporation rate of 2.84 kg·m⁻²·h⁻¹, significantly outperforming similar devices. Additionally, it maintains high operational stability over 14 days of continuous evaporation in simulated seawater salinity without any salt accumulation on the surface. Moreover, the 3DGZ-Ni@CNTG material efficiently photocatalyzes CO₂ reduction to produce CO at relatively low temperatures, with high selectivity. The H₂O (water vapor) generated by the solar-driven photothermal evaporation process, along with CO produced from CO₂ reduction, can serve as key components of the water-gas shift reaction (mainly CO and H₂O), a key process in the synthetic chemical industry. This provides a new idea for the integrated use of “solar energy-freshwater-carbon-based chemicals,” creating a closed-loop material cycle.