Improved Interface Charge Transfer and Redistribution in CuO‐CoOOH p‐n Heterojunction Nanoarray Electrocatalyst for Enhanced Oxygen Evolution Reaction

Abstract

Electron density modulation is of great importance in an attempt to achieve highly active electrocatalysts for the oxygen evolution reaction (OER). Here, the successful construction of CuO@CoOOH p-n heterojunction (i.e., p-type CuO and n-type CoOOH) nanoarray electrocatalyst through an in situ anodic oxidation of CuO@CoS x on copper foam is reported. The p-n heterojunction can remarkably modify the electronic properties of the space-charge region and facilitate the electron transfer. Moreover, in situ Raman study reveals the generation of SO 4 2− from CoS x oxidation, and electron cloud density distribution and density functional theory calculation suggest that surface-adsorbed SO 4 2− can facilitate the OER process by enhancing the adsorption of OH − . The positively charged CoOOH in the space-charge region can significantly enhance the OER activity. As a result, the CuO@CoOOH p-n heterojunction shows significantly enhanced OER performance with a low overpotential of 186 mV to afford a current density of 10 mA cm −2 . The successful preparation of a large scale (14 × 25 cm 2 ) sample demonstrates the possibility of promoting the catalyst to industrial-scale production. This study offers new insights into the design and fabrication of non-noble metal-based p-n heterojunction electrocatalysts as effective catalytic materials for energy storage and conversion.

Robust Porous WC‐Based Self‐Supported Ceramic Electrodes for High Current Density Hydrogen Evolution Reaction

“…The binding energy of the characteristic W 4f XPS peak of W in WC‐N/W‐1200 is higher than that of single‐phase W. This is an indication of electrons transfer from W to WC in WC‐N/W heterostructure, which is a reflection of the Mott–Schottky effect. [ 27 ] The higher and wider binding energy of W‐C peak in WC‐N/W‐1200, compared to that in WC single‐phase, is attributed to the doping effect of the strongly electronegative N element, [ 28 ] which is consistent with the previous XPS analysis results. And also, in the N‐free WC/W heterostructure, the binding energy of the W peak is higher than that of the single‐phase W, and the binding energy of the W‐C peak is lower than that of the single‐phase WC, which also indicates that electrons transfer from W to WC at the WC/W interface.…”

Amino Modified Carbon Dots with Electron Sink Effect Increase Interface Charge Transfer Rate of Cu‐Based Electrocatalyst to Enhance the CO2 Conversion Selectivity to C2H4

“…The HRTEM image (Figure 1D) of CuO‐NCDs‐2 shows well‐defined lattice spacing of ≈0.23 nm and ≈0.21 nm, which are consistent with the (1 1 1) plane of CuO and (1 0 0) plane of NCDs, respectively, indicating that NCDs are compounded with CuO. [ 39 ] Meanwhile, Figure S1 (Supporting Information) shows the TEM and HRTEM images of CuO. The morphology and particle size of CuO and CuO‐NCDs‐2 are similar, mainly composed of particles with a size range of 500–1000 nm.…”

Cu2O/CeO2 Photo‐electrochemical Water Splitting: A Nanocomposite with an Efficient Interfacial Transmission Path under the Co‐action of a p–n Heterojunction and Micro‐mesocrystals

“…Therefore, the significant PL quenching and the shortened average lifetime of Cu 2 O/CeO 2 ‐2 can be ascribed to the self‐assembly CeO 2 m‐MCs structures further promoting effective charge separation/transfer [31] . In addition, the EIS displayed in Figure S15c further verified that Cu 2 O/CeO 2 ‐2 has the smallest radius, suggesting the best interface charge transfer ability of Cu 2 O/CeO 2 ‐2 [7,24,39] . Compared with Cu 2 O, the radius of other composites decreased significantly, demonstrating that p–n heterojunction can promote charge transfer.…”

“…[31] In addition, the EIS displayed in Figure S15c further verified that Cu 2 O/CeO 2 -2 has the smallest radius, suggesting the best interface charge transfer ability of Cu 2 O/CeO 2 -2. [7,24,39]…”

“…However, the severe electron–hole recombination and photocorrosion dramatically reduce its actual catalytic performance [5] . To address these drawbacks, plenty of strategies have been developed, [6] among which p–n heterojunction engineering has been regarded as a promising approach [1a,b,7] . For example, the heterostructured photoelectrodes such as Ti 2 O@Cu 2 O, [8] g‐C 3 N 4 /Cu 2 O, [9] and Cu 2 O/BiVO 4 , [10] show improved catalytic performance.…”