Synthesis of reduced graphene oxide supported nickel-cobalt-layered double hydroxide nanosheets for supercapacitors.

The poor conductivity, unsatisfactory stability, and severe aggregation of nanosheets have been recognized as the main reasons that limit the electrochemical performance of layered double hydroxide...

NiMn Layered Double Hydroxide Nanosheets In-situ Anchored on Ti3C2 MXene via Chemical Bonds for Superior Supercapacitors

The oxygen reduction reaction (ORR) is an extremely important reaction in many renewable energy-related devices. The sluggish kinetics of the ORR limits the development of many fuel cells. Design and synthesis of highly efficient nonprecious electrocatalysts are of vital importance for electrochemical reduction of oxygen. Herein, we develop a graphitic carbon nitride (g-C3N4)-derived bamboo-like carbon nanotubes/carbon-wrapped Co nanoparticles (BCNT/Co) electrocatalyst by a simple high-temperature pyrolysis and acid-leaching method. The catalytic performance of the as-designed electrocatalyst toward ORR outperforms the commercial Pt/C catalyst in alkaline solution. The onset potential of nonprecious BCNT/Co-800 catalyst was 1.12 V. The half-wave potential was 0.881 V. The result was superior to that of commercial Pt/C (0.827 V vs RHE). The Co nanoparticles, bamboo-like carbon nanotubes, defects, and Co-Nx active sites all result in the remarkable ORR activity, stability, and great methanol tolerance.

Graphitic Carbon Nitride (g-C3N4)-Derived Bamboo-Like Carbon Nanotubes/Co Nanoparticles Hybrids for Highly Efficient Electrocatalytic Oxygen Reduction.

Advances in Zeolite Imidazolate Frameworks (ZIFs) Derived Bifunctional Oxygen Electrocatalysts and Their Application in Zinc–Air Batteries

Water splitting has been regarded as a sustainable and environmentally-friendly technique to realize green hydrogen generation, while more energy is consumed due to the high overpotentials required for the anode oxygen evolution reaction. Urea electrooxidation, an ideal substitute, is thus received increasing attention in assisting water-splitting reactions. Note that highly efficient catalysts are still required to drive urea oxidation, and the facile generation of high valence state species is significant in the reaction based on the electrochemical-chemical mechanisms. The high cost and rareness make the noble metal catalysts impossible for further consideration in large-scale application. Ni-based catalysts are very promising due to their cheap price, facile structure tuning, good compatibility, and easy active phase formation. In the light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based powder catalysts for urea oxidation in assisting water-splitting reaction. The fundamental of urea oxidation is firstly presented to clarify the mechanism of urea-assisted water splitting, and then the prevailing evaluation indicators are briefly expressed based on the electrochemical measurements. The catalyst design principle including synergistic effect, electronic effect, defect construction and surface reconstruction as well as the main fabrication approaches are presented and the advances of various Ni-based powder catalysts for urea assisted water splitting are summarized and discussed. The problems and challenges are also concluded for the Ni-based powder catalysts fabrication, the performance evaluation, and their application. Considering the key influencing factors for catalytic process and their application, attention should be given to structure−property relationship deciphering, novel Ni-based powder catalysts development and their construction in the real device; specifically, the effort should be directed to the Ni-based powder catalyst with multi-functions to simultaneously promote the fundamental steps and high anti-corrosion ability by revealing the local structure reconstruction as well as the integration in the practical application. We believe the current summarization will be instructive and helpful for the Ni-based powder catalysts development and understanding their catalytic action for urea-assisted hydrogen generation via water splitting technique. Advances and challenges of Ni based powder catalyst were reviewed for urea oxidation in assisting water-splitting reaction. 

A review of Ni based powder catalyst for urea oxidation in assisting water splitting reaction

M-N-C electrocatalysts for the oxygen reduction reaction (ORR) have been considered as the most promising alternatives to precious metal catalysts. However, the catalytic activity of M-N-C especially in an acidic medium is still unable to meet the practical requirement, and the corresponding ORR mechanism also remains unclear. Herein, an "MOF-protective-pyrolysis" strategy was adopted to synthesize an Fe-N-C catalyst (P-FeMOF@ZIF-8) with Fe-N4 as the predominant Fe species. The P-FeMOF@ZIF-8 displays high catalytic activity in both acidic and alkaline mediums. The experimental results further reveal the different importance of the Fe species in different mediums. Based on the results, a distinct mechanism of the ORR the in acidic medium was proposed, where the synergistic effect of the Fe-N4 site and carbon in improving the kinetics of the ORR were well explained. The findings and the corresponding perspective may provide a new guidance for the design of highly efficient ORR electrocatalysts.

A “MOF-Protective-Pyrolysis” Strategy for the Preparation of Fe–N–C Catalysts and the Role of Fe, N, and C in the Oxygen Reduction Reaction in Acidic Medium

Dandan Wei

Papers

A “MOF-Protective-Pyrolysis” Strategy for the Preparation of Fe–N–C Catalysts and the Role of Fe, N, and C in the Oxygen Reduction Reaction in Acidic Medium

CNT/Co3S4@NiCo LDH ternary nanocomposites as battery-type electrode materials for hybrid supercapacitors

Hairy sphere-like Ni9S8/CuS/Cu2O composites grown on nickel foam as bifunctional electrocatalysts for hydrogen evolution and urea electrooxidation

Unveiling the real active sites of Ni based metal organic framework electrocatalysts for the oxygen evolution reaction

Improving the electrocatalytic activity of NiFe bimetal-organic framework toward oxygen evolution reaction by Zr doping