Ag/g-C3N4 nanosheets as a progressive support of Pt catalyst for improved electrocatalytic oxidation of methanol

In consideration of the increased activity of Pt-based catalysts for methanol oxidation in direct methanol fuel cells, it is necessary to apply an ideal support in the construction of Pt-based catalyst for methanol oxidation. In this study, Ag/g-C(3)N(4 )nanosheets (Ag/GCNN) nanocomposites with different Ag contents were synthesized and used as the progressive support to construct Pt/Ag/GCNN catalyst. As a nitrogen-rich polymeric semiconductor, GCNN is easily coordinated with various metals. The introduction of Ag nanoparticles can improve the electrical conductivity of the catalyst and cooperate with Pt for optimizing the performance of electrocatalytic oxidation of methanol. The electrochemical experiment results demonstrated that Pt/Ag/GCNN has higher electrocatalytic activity and stability for methanol oxidation than Pt/GC and Pt/GCNN. The mass activity of Pt/Ag/GCNN-0.6 (18.66 mA mgPt(-1)) is 7.07, 4.60 and 1.26 times that of Pt/GCNN (4.06 mA mgPt(-1)), Pt/Ag/GCNN-0.4 (4.06 mA mgPt(-1)) and Pt/Ag/GCNN-0.8 (14.76 mA mgPt(-1)) at the forward peak potential. The Jf/Jb ratio of Pt/Ag/GCNN-0.6 is 3.31, which is bigger than that of Pt/GCCN (2.62), Pt/Ag/GCNN-0.4 (2.69), and Pt/Ag/GCNN-0.8 (2.56). A suitable mechanism was proposed to explain that Ag/GCNN supported Pt catalyst can improve the CO toxicity resistance and electrocatalytic performance. Based on the coordination of GCNN, Ag was first modified to form a support, and then the remaining coordination sites were used to support Pt. It provided a new strategy for the design of catalysts for methanol electrooxidation.