Carbon cloth supporting spinel CuMn0.5Co2O4 nanoneedles with the regulated electronic structure by multiple metal elements as catalysts for efficient oxygen evolution reaction

Ferric citrate corroding nickel foam to synthesize carbon quantum dots@nickel-iron layered double hydroxide microspheres for efficient water oxidation

The design of oxygen evolution reaction (OER) catalysts with high catalytic efficiency and durability is of great significance for promoting hydrogen production via water electrolysis. Here, a one-step hydrothermal method was used to synthesize carbon quantum dots@nickel-iron layered double hydroxide (CQDs@NiFe-LDH) composites based on corrosion engineering. The introduction of carbon quantum dots (CQDs) effectively modulates the electronic structure and charge distribution of nickel-iron layered double hydroxide (NiFe-LDH), resulting in high oxygen evolution reaction with an overpotential of 257 mV at 100 mA cm-2 and a small Tafel slope of 38.73 mV dec-1. Furthermore, CQDs@NiFe-LDH can be operated continuously for 300 and 100 h without the significant performance degradation at a current density of 100 mA cm-2 in 1 M KOH and seawater solutions, respectively, indicating high catalytic stability. The excellent OER capabilities of CQDs@NiFe-LDH is attributed to the fact that CQDs can not only modulate the electronic structure of NiFe-LDH but also facilitate the transfer of protons between intermediates during the oxygen evolution reaction (OER), thereby enhancing the material's intrinsic catalytic activity.

Electron regulation of CeO2 on CoP multi-shell hetero-junction micro-sphere towards highly efficient water oxidation

CeO2 has been identified as a significant cocatalyst to enhance the electrocatalytic activity of transition metal phosphides (TMPs). However, the electrocatalytic mechanism by which CeO2 enhances the catalytic activity of TMP remains unclear. In this study, we have successfully developed a unique CeO2-CoP-1-4 multishell microsphere heterostructure catalyst through a simple hydrothermal and calcination process. CeO2-CoP-1-4 exhibits great potential for electrocatalytic oxygen evolution reaction (OER), requiring only an overpotential of 254 mV to achieve a current density of 10 mA cm-2. Moreover, CeO2-CoP-1-4 demonstrates excellent operating durability lasting for 55 h. The presence of CeO2 as a cocatalyst can regulate the microsphere structure of CoP, the resulting multishell microsphere structure can shorten the mass transfer distance, and improve the utilization rate of the active site. Furthermore, in situ Raman and ex situ characterizations, and DFT theoretical calculation results reveal that CeO2 can effectively regulates the electronic structure of Co species, reduces the reaction free energy of rate-limiting step, thus increase the reaction kinetic. Overall, this study provides experimental and theoretical evidence to better comprehend the mechanism and structure evolution of CeO2 in enhancing the OER performance of CoP, offering a unique design inspiration for the development of efficient hollow heterojunction electrocatalysts.

Carbon-Based Composites for Oxygen Evolution Reaction Electrocatalysts: Design, Fabrication, and Application

The four-electron oxidation process of the oxygen evolution reaction (OER) highly influences the performance of many green energy storage and conversion devices due to its sluggish kinetics. The fabrication of cost-effective OER electrocatalysts via a facile and green method is, hence, highly desirable. This review summarizes and discusses the recent progress in creating carbon-based materials for alkaline OER. The contents mainly focus on the design, fabrication, and application of carbon-based materials for alkaline OER, including metal-free carbon materials, carbon-based supported composites, and carbon-based material core-shell hybrids. The work presents references and suggestions for the rational design of highly efficient carbon-based OER materials.