Cu2O photocatalyst: Activity enhancement driven by concave surface. (June 2020)

• Record Type: Journal Article
• Authors: Lu, Xinxin; Hart, Judy N.; Yao, Yin; Toe, Cui Ying; Scott, Jason; Ng, Yun Hau
• Is Part Of: Materials today energy. Volume 16(2020)
• Publication Date: 2020-06
• Subjects: Cu2O concave surface -- Photoelectrochemistry -- Photocatalytic activity -- DFT calculations -- KPFM measurement; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2020.100422
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: The study of the Cu2 O concave surfaces has attracted significant attention, in which most work to date has focused primarily on investigating the formation mechanism and catalytic performance. However, the photoinduced charge behavior of concave surfaces and the origins of improved photocatalytic performance, that are important for understanding photogenerated charge separation and migration, have not been thoroughly explored. Here, we demonstrate that the presence of concave surfaces on the Cu2 O {100} facet facilitates the capture of photogenerated electrons. Density functional theory (DFT) calculations of the surface energies and charge distribution revealed that the concave surfaces are catalytically active due to the presence of under-coordinated copper atoms with increased charge relative to copper atoms on flat surfaces. This was further supported by comparing the surface potentials of the concave and flat regions on the Cu2 O {100} surface, which were measured by Kelvin probe force microscopy (KPFM). The obtained surface potentials confirmed that the {100} concave surfaces have a gradient decrease of surface work function, inducing an efficient built-in electric field. This was visually demonstrated by the selective photodeposition of Pt particles on the concavities of the {100} surfaces. The charge distribution effect was observed and verified by both the theoretical and experimental means, whereby Cu2 O particles with the {100} concave surfaces exhibited better performance in both photoelectrochemical (PEC) measurement and photocatalytic H2 evolution. Graphical abstract: Image 1 Highlights: Cu2 O {100} concave surface was studied by experimental and theoretical approaches. Concave surfaces facilitated photoinduced charge separation and migration. Cu2 O with {100} concave surfaces showed better PEC and H2 evolution performance.