Hollow spherical Ni/ZrO2 as a superior catalyst for syngas production from photothermal synergistic dry reforming of methane

Abstract

Dry reforming of methane (DRM) is appealing for syngas production yet challenging due to its high reactive energy barrier and catalyst deactivation. To address the issues in traditional thermocatalytic (TC) DRM, this paper investigated DRM under photothermal synergistic catalytic (PTSC) conditions. The synthesized Ni/ZrO₂ catalyst with a hollow sphere structure (sp-Ni/ZrO₂) demonstrated excellent performance in suppressing metal sintering and carbon deposition. The hollow sphere structure effectively enhanced the catalyst's light absorption ability, which can broaden spectrum absorption and decrease the bandgap from 4.9 eV to 4.2 eV, and effectively enhanced the synergistic photocatalysis. Under PTSC conditions at 600 °C, the catalyst achieved CO and H₂ yields of 73.4 mmol g⁻¹ h⁻¹ and 63.7 mmol g⁻¹ h⁻¹, respectively, while maintaining stability for 18 hours. The activation energies for CO₂ and CH₄ dissociation under PTSC are 27.2 kJ mol⁻¹ and 32.9 kJ mol⁻¹, significantly lower than the corresponding values of 40.0 kJ mol⁻¹ and 44.4 kJ mol⁻¹ under TC conditions. Besides, the turnover frequencies of CH₄ and CO₂ for sp-Ni/ZrO₂ range from 0.35 to 1.19 s⁻¹ and 0.47 to 1.37 s⁻¹, respectively, which are 1.1–2.1 times higher than those in TC-DRM. This paper provides a new perspective on PTSC catalyst design and offers an innovative solution to overcome the limitations of conventional DRM reactions.