BiVO₄ Microparticles Decorated with Cu@Au Core-Shell Nanostructures for Photocatalytic H₂O₂ Production

Abstract

The nanostructured Au cocatalyst modification of BiVO4 photocatalyst, as a prospective method, can significantly promote its photocatalytic H2O2 production performance. However, the contact between Au and BiVO4 causes a strong built-in field, which impedes the photogenerated-electron transfer and the accumulation of negative charge density for Au, which reduces its catalytic activity of two-electron O2 reduction, thus limiting the enhanced H2O2 production performance of the Au/BiVO4 photocatalyst. To solve the above problems, here, a Cu@Au core-shell nanostructured cocatalyst is designed to selectively modify on the electron-enriched (010) facet of a single-crystal BiVO4 microparticle by facile photodeposition and subsequently galvanic displacement. In this case, ohmic contact between the Cu nanoparticle and (010) facet of BiVO4 can effectively transfer the photogenerated electrons to the Au cocatalyst and simultaneously facilitate the catalytic activity improvement of two-electron O2 reduction for the Au cocatalyst due to its low negative charge accumulation. As a result, the optimized BiVO4 photocatalyst with Cu@Au core-shell nanostructured modification exhibits obviously improved photocatalytic performance of H2O2 formation (91.1 μmol L–1) compared with Au/BiVO4 (62.5 μmol L–1). The present strategy of a bimetal cocatalyst with a core-shell nanostructure opens up an insight to explore effective photocatalytic materials for the application of H2O2 production.

Highly efficient photocatalytic H2O2production in microdroplets: accelerated charge separation and transfer at interfaces

“…[1][2][3] Currently, over 95% of H 2 O 2 production is dependent on the multistep anthraquinone hydrogenation-oxidation process, which is energy-consuming and waste-intensive. 4,5 As an alternative, direct H 2 O 2 synthesis from H 2 and O 2 using Pd, Au-based catalysts is inevitably associated with high explosion risk, limiting the industrial application. 6 Thus, it is desirable to develop an energy-saving pathway for efficient H 2 O 2 synthesis.…”

Nanostructured NiCo2O4/BiVO4 Heterojunctions for Visible-Light Photocatalytic H2O-to-H2O2 Synchronized Organic Pollutant Oxidation

“…For example, under visible-light irradiation for 40 min, about 83% and 45% H 2 O 2 were yielded and decomposed, respectively, by NiCo 2 O 4 /BiVO 4 , while very low rates for H 2 O 2 formation and decomposition, respectively, by BiVO 4 were observed (see Figure C). The competitive reaction between photocatalytic H 2 O 2 formation and decomposition was investigated by the following equation: H 2 O 2 = k f / k d (1 – exp­(− k d t )), where k f and k d are the rate constants of H 2 O 2 formation and decomposition, respectively. Also, Table S2 shows the reaction rate constants for k f and k d and the equilibrium constant ( K ) for reversible H 2 O 2 formation.…”

The enhanced photocatalytic properties of Bi/BiOCl composites for H2O2 production

“…As shown in Table S1 (ESI†), the concentrations of H 2 O 2 generated by most bismuth-based catalysts are at the micromole level, but the H 2 O 2 output of the as-prepared Bi/BiOCl has reached the millimolar level, demonstrating the excellent photocatalytic activity and selectivity. 45–47…”

“…As shown in Table S1 (ESI †), the concentrations of H 2 O 2 generated by most bismuth-based catalysts are at the micromole level, but the H 2 O 2 output of the as-prepared Bi/ BiOCl has reached the millimolar level, demonstrating the excellent photocatalytic activity and selectivity. [45][46][47] To investigate the factors that caused the enhanced photocatalytic performance of the Bi nanoparticle modified BiOCl composites, UV-Vis absorption spectra, transient photocurrent response (TPR) and photoluminescence (PL) spectrum were recorded. Fig.…”