Designing p‐Type Semiconductor–Metal Hybrid Structures for Improved Photocatalysis

Abstract

A practical strategy is proposed to facilitate the migration of holes in semiconductor (the low rate of which limits photocatalytic efficiency) by taking advantage of the Schottky barrier between p‐type semiconductor and metal. A high work function is found to serve as an important selection rule for building such desirable Schottky junction between semiconductor surface facets and metal. The intrinsic charge spatial distribution has to be taken into account when selecting the facets, as it results in accumulation of photoexcited electrons and holes on certain semiconductor facets. Importantly, the facets have a high work function, the same characteristic required for the formation of Schottky junction in a p‐type semiconductor–metal hybrid structure. As a result, the semiconductor crystals in the hybrid design may be better enclosed by single facets with high work function, so as to synergize the two effects: Schottky barrier versus charge spatial separation.

Boosting Photocatalytic Activity in Cross‐Coupling Reactions by Constructing Pd‐Oxide Heterostructures

“…Cu 2 O cube with a wide absorption region could be excited by the ultraviolet and visible light in a wavelength range of 200–700 nm, producing photogenerated electron‐hole pairs. Then photogenerated holes can transfer to supported Pd through the {100} facets of Cu 2 O cube, leaving the electrons in the Cu 2 O . The opposite transfer situation of photogenerated carriers alters the electron density on Pd, leading to the distinct activity change of Pd NP‐TiO 2 NS and Pd NP‐Cu 2 O cube under energetic light illumination.…”

Surface/Interfacial Catalysis of (Metal)/Oxide System: Structure and Performance Control

“…Wang and co‐workers observed that the Cu 2 O cuboctahedrons with both (1 0 0) and (1 1 1) facets exhibited three times higher in coefficient of photocurrent than the Cu 2 O cubes with solo (1 0 0) or (1 1 1) facets. The unique electronic structure of (1 0 0) facet causes a higher work function (approx.…”

Selective Deposition of Cobalt and Copper Oxides on BiVO4 Facets for Enhancement of CO2 Photocatalytic Reduction to Hydrocarbons

“…It is generally believed that photocatalysts exhibit better catalytic properties when more active crystal facets are exposed to reacting molecules. [18,19] In many classical photocatalytic semiconductors, it has been shown that controlling the exposure of a suitable crystal facets is an effective strategy to improve photocatalytic performance, for example: TiO 2 , [20,21] BiVO 4 , [22][23][24] Cu 2 O, [25,26] and CeO 2 . [27] In photocatalytic reactions, the high recombination rate of photogenerated electrons and holes is a major factor limiting its photocatalytic performance.…”