Enhanced Electrocatalytic Oxidation of Methanol on Pt‐Decorated Bi₂WO₆/Graphene Nanosheets with Visible Light Assistance

Abstract

Noble metal/semiconductor–based electrocatalysts have been proverbially used as the anode material in direct methanol fuel cells (DMFCs) recently. Combined with the advantage of the properties of noble metals and semiconductors, photo‐assisted electrocatalytic methanol oxidation is a valid route to increase the catalytic activity of catalysts in DMFCs. Herein, a 2D composite of bismuth tungstate/reduced graphene oxide (Bi2WO6/RGO) with excellent optical, electrical, and thermal stability is used as the support for the decoration of platinum nanoparticles (Pt NPs) to synthesize a new electrocatalyst of Pt‐Bi2WO6/RGO. Under ambient conditions, the methanol oxidation reaction (MOR) activity of the Pt‐Bi2WO6/RGO electrocatalyst increases relative to the Pt/Bi2WO6 electrode. Note that, under visible light irradiation, it deals with big enhancement of methanol oxidation activity on Pt‐Bi2WO6/RGO electrode, highlighting the effect of RGO used as Bi2WO6 cocatalysis for the MOR activity under illumination. Meanwhile, the corresponding reaction mechanisms with/without visible light are presented, and the roles of Pt‐Bi2WO6/RGO for photo‐assisted electrochemical reactions are proposed.

Noble Metal‐Free CoSx/NiSx Heterojunction for Photo‐Assisted Methanol Electrooxidation

“…So the CoS x /NiS x (4 : 1) heterojunction was use for the following investigation. According to the previous report, [9] the light‐to‐current efficiency ( η ) can be used for illustrating the photocurrent contributes to the efficiency of the fuel cell. The η of CoS x /NiS x heterojunction can be expressed by equation (1), where J PEC and J EC represent the current densities of CoS x /NiS x with and without light at 0.6 V. …”

“…Previous report [4] indicated that, the active oxygen sources (e. g., O ads and OH ads ) from the dissociation of water is one of the prerequisites to oxidize intermediate CO ads . In order to improve the efficiency of water dissociation, semiconductor materials, such as TiO 2 , [5] WO 3 , [6] CdS, [7] C 3 N 4 , [8] Bi 2 WO 6, [9] and ZnO, [10] have been certified as promising support for Pt and other precious metal (Au and so on) electrocatalyst because of the excellent photoelectronic properties and enhanced photoelectrocatalytic water dissociation activity. In such photo‐assisted fuel cell system, the methanol molecules are oxidized at the surface of a noble metal/semiconductor anode through synergistic electrocatalytic and photocatalytic routes under light illumination.…”

Metal organic framework-derived transition metal-doped CoSx nanocage for enhanced visible light-assisted methanol electrocatalytic oxidation

“…42 These properties contribute to the visible-light harvesting ability and high charge mobility of metal sulfides. 43,44 According to the previous report, 45 the light-to-current efficiency (Z) can be used for illustrating the photocurrent contributes to the efficiency of the fuel cell. The Z of CoS x can be expressed by eqn (1), where J PEC and J EC represent the current densities of CoS x with and without light irradiation at 0.6 V, respectively.…”