Regulating crystal phase of TiO2 to enhance catalytic activity of Ni/TiO2 for solar-driven dry reforming of methane

Ni/TiO 2 catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO 2 remains unclear. In this work, the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO 2 . Structural characterizations revealed that a distinct TiO x coating on the Ni nanoparticles (NPs) was evident for Ni/TiO 2 -700 catalyst due to strong metal-support interaction. It is observed that the TiO x overlayer gradually disappeared as the ratio of rutile/anatase increased, thereby enhancing the exposure of Ni active sites. The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH 4 , which led to the much elevated catalytic activity for Ni/ TiO 2 -950 in which rutile dominated. Therefore, the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio. Ni/TiO 2 -950, characterized by a predominant rutile phase, exhibited the highest DRM reactivity, with remarkable H 2 and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h), respectively. These rates were approximately 257 and 130 times higher, respectively, compared to those obtained on Ni/TiO 2 -700 with anatase. This study suggests that the optimization of crystal structure of TiO 2 support can effectively enhance the performance of photothermal DRM reaction.