Enhanced hybrid photocatalytic dry reforming using a phosphated Ni-CeO2 nanorod heterostructure

Operating the dry reforming reaction photocatalytically presents an opportunity to produce commodity chemicals from two greenhouse gases, carbon dioxide and methane, however, the top-performing photocatalysts presented in the academic literature invariably rely on the use of precious metals. In this work, we demonstrate enhanced photocatalytic dry reforming performance through surface basicity modulation of a Ni-CeO2 photocatalyst by selectively phosphating the surface of the CeO2 nanorod support. An optimum phosphate content is observed, which leads to little photoactivity loss and carbon deposition over a 50-hour reaction period. The enhanced activity is attributed to the Lewis basic properties of the PO43- groups which improve CO2 adsorption and facilitate the formation of small nickel metal clusters on the support surface, as well as the mechanical stability of CePO4. A hybrid photochemical-photothermal reaction mechanism is demonstrated by analyzing the wavelength-dependent photocatalytic activities. The activities, turnover numbers, quantum efficiencies, and energy efficiencies are shown to be on par with other dry-reforming photocatalysts that use noble metals, representing a step forward in understanding how to stabilize ignoble nickel-based dry reforming photocatalysts. The challenges associated with comparing the performance of photocatalysts reported in the academic literature are also commented on. The top-performing dry reforming photocatalysts in the literature rely on the use of precious metals. Here, enhanced photocatalytic dry reforming performance is reported through surface basicity modulation of a Ni/CeO2 photocatalyst, achieved by selectively phosphating the surface of a CeO2 nanorod support.

Automated summary

This study demonstrates improved photocatalytic dry reforming performance by selectively phosphating the surface of a CeO2 nanorod support to modulate the surface basicity of a Ni-CeO2 photocatalyst. An optimum phosphate content is found, leading to little activity loss and carbon deposition over a 50-hour reaction period. The enhanced performance is attributed to the Lewis basic properties of the PO43- groups, which improve CO2 adsorption, facilitate the formation of small nickel metal clusters, and provide mechanical stability. A hybrid photochemical-photothermal reaction mechanism is also demonstrated.