Synergistic ZrO2 effects in Co/In2O3 catalysts: Enhancing activity and selectivity for CO2 hydrogenation to methanol

Abstract

The In₂O₃-ZrO₂ solid solution catalyst has emerged as a versatile catalytic support for CO₂ hydrogenation to methanol, enabling noble metal-based systems (e.g., Pt, Ir) to achieve improved methanol selectivity. Building on this foundation, we introduce cobalt into the In₂O₃-ZrO₂ matrix, creating a novel Co/In₂O₃-ZrO₂ composite catalyst that synergistically integrates transition metal functionality with oxide engineering. The optimized catalyst achieves a methanol space-time yield of 0.80 g_MeOH·gcat⁻¹·h⁻¹ at a 5.0 MPa, H₂/CO₂ = 3:1, 320 °C, GHSV = 48,000 cm³·$g_{\mathrm{cat}}^{-1}·$h⁻¹, surpassing reported In₂O₃-ZrO₂ and Co/In₂O₃ benchmarks. Mechanistic studies reveal that methanol synthesis follows the formate pathway, where ZrO₂ amplifies oxygen vacancy density to improve CO₂ adsorption and weakens CO adsorption through electronic modulation.