Solar-Light-Driven CO_2 Reduction by CH_4 on Silica-Cluster-Modified Ni Nanocrystals with a High Solar-to-Fuel Efficiency and Excellent Durability

摘要

Catalytic CO2 reforming of CH4 (CRM) to produce syngas (H-2 and CO) provides a promising approach to reducing global CO2 emissions and the extensive utilization of natural gas resources. However, the rapid deactivation of the reported catalysts due to severe carbon deposition at high reaction temperatures and the large energy consumption of the process hinder its industrial application. Here, a method for almost completely preventing carbon deposition is reported by modifying the surface of Ni nanocrystals with silica clusters. The obtained catalyst exhibits excellent durability for CRM with almost no carbon deposition and deactivation after reaction for 700 h. Very importantly, it is found that CRM on the catalyst can be driven by focused solar light, thus providing a promising new approach to the conversion of renewable solar energy to fuel due to the highly endothermic characteristics of CRM. The reaction yields high production rates of H-2 and CO (17.1 and 19.9 mmol min(-1) g(-1), respectively) with a very high solar-to-fuel efficiency (eta, 12.5%). Even under focused IR irradiation with a wavelength above 830 nm, the eta of the catalyst remains as high as 3.1%. The highly efficient catalytic activity arises from the efficient solar-light-driven thermocatalytic CRM enhanced by a novel photoactivation effect.