Revealing La doping activation or inhibition of crystal facet effects in Co3O4 for catalytic combustion and water resistance improvement

Abstract

It was challenging to enhance the catalytic activity and water resistance of transition metal oxides in the CH4 treatment process. Here, La with large atomic radii was doped onto Co3O4 on the (110), (111) and (100) crystal facets, respectively, and successfully doped into the (110) and (100) lattices, but accumulation occurs on the (111) crystal surface. Doping La into the Co3O4 lattice achieved a dual excitation effect for surface optimization and structural defects, causing lattice expansion, enhancing the electrophilicity of the O atoms in the vicinity of La, and significantly stimulating the Co-O bond. This significantly improved reactive oxygen species content, CH4 adsorption capacity, and gaseous oxygen activation and replenishment capability for higher catalytic activity. Conversely, the (111) facet with accumulated La showed an opposite trend. Meanwhile, La doping effectively improved the stability of Co3O4 and weakened its hydrophilicity, which effectively enhanced its water resistance. This research provided a viable strategy for designing high-performance and water-resistant Co3O4-based catalysts.