Incorporation of NiO on attapulgite supported Au catalyst for HCHO removal at low temperature

Gold-based catalysts are renowned for their exceptional low-temperature oxidation activity and have found widespread application in the thermos catalytic oxidation of formaldehyde (HCHO). In this study, an in-situ hydrothermal synthesis method was employed to prepare Au_0.5Ni_x/ATP catalysts. By altering the doping amount of Ni during the synthesis process, the impact of Ni doping on the catalytic reactivity was investigated. Compared to pure gold-based catalysts, the dispersion and sintering resistance of the Au_0.5Ni_x/ATP catalysts were enhanced. The OH^- ions present in the alkaline solution provided by TPAOH disrupted the morphology of ATP, leading to a flocculent appearance for the Au_0.5/ATP catalyst. With varying doping levels of Ni, the rod-like structure of ATP gradually recovered due to the strong interaction between Ni²⁺ and OH-. On the Au_0.5Ni_x/ATP catalysts, NiO, being a p-type semiconductor, was prone to electron loss, with the lost electrons being captured by Au³⁺ to form Au⁰ and stronger Au and Ni interactions. When Ni species were introduced onto the Au/ATP surface, the synergistic effect between Au and Ni resulted in higher catalytic activity, favoring the catalytic oxidation of HCHO. The catalytic efficiency peaked when the Ni doping level reached 20 wt%.