2020同步年報

062 ACTIVITY REPORT 2020 demonstrated that the generation of defects in D‐IrTe 2 and DO‐IrTe 2 HNS during electrochemical reconstruction could reg- ulate the local coordination environment and electronic structure of Ir, and thus boost the electrochemical water-splitting reaction. Shaohua Shen (Xi’an Jiaotong University, China) and his coworkers recently developed also a ternary nanostructured α-Fe 2 O 3 / Au/TiO 2 film for photoelectrocatalytic water splitting. Under simulated solar illumination, the photoanode as prepared exhib- ited a four-fold increase in photocurrent density relative to bare α-Fe 2 O 3 . Recording soft XAS at TLS 20A1 , 3 Shen’s team eluci- dated the origin of the enhancement and the underlying mechanisms determining the photoelectrocatalytic water-splitting performances, as shown in Fig. 3 . Based on systematic investigations, it is proposed that Au NP extract photoholes from the bulk of an α-Fe 2 O 3 core and then shuttle them to the outer TiO 2 overlayer; this TiO 2 overlayer concurrently efficiently captures and stores the photoholes and facilitates the hole injection into the electrolyte. The remarkably improved photoelectrocat- alytic water-splitting performance of an α-Fe 2 O 3 /Au/TiO 2 photoanode is thus attributed to the significant suppression of recombination of bulk and surface charge by means of the relayed pumping of the photogenerated charge carriers through the photoanode and electrolyte interfaces reconstructed by Au NP and the TiO 2 overlayer. Fig. 3 : XAS of (a) Fe L-edge, (b) Ti L-edge, and (c), (d) O K-edge; right part of (a) and left part of (d) are the corresponding enlarged regions marked with dashed boxes. (e) Ti L-edge and (f) Fe L-edge in darkness. Peaks in (e) are deconvoluted into three components (peaks A, B and C); the solid lines in the inset represent the tested data and the circles indicate the fitted spectra. (g) O K-edge of α-Fe 2 O 3 /Au/TiO (red solid line) and a fitted spectrum (open solid circles) calculated from a linear combination of spectra of α-Fe 2 O 3 /Au and α-Fe 2 O 3 /TiO 2 . [Reproduced from Ref. 3]