Our group synthesized Cs-salts of theKeggin-type phosphomolybdic acid with simultaneous doping of VO2+ and differenttransition metals, and found that, due to the synergistic effect betweenco-substituted VO2+ and Cu2+ in its secondary structure, Cs2.0V0.3Cu0.2PMo12O40catalyst with exhibits higher catalytic performance for the oxidation ofisobutane to methacrylic acid. This work has been published in CatalysisScience & Technology, 2018, 8, 5774-5781.