The construction of highly active and stable non-noble-metal electrocatalysts for hydrogen and oxygen evolution reactions is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP nanoparticles (NPs) embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis–oxidation–phosphidation strategy derived from core–shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances. When the CoP/NCNHP was employed as both the anode and cathode for overall water splitting, a potential as low as 1.64 V was needed to achieve the current density of 10 mA·cm–2, and it still exhibited superior activity after continuously working for 36 h with nearly negligible decay in potential. Density functional theory calculations indicated that the electron transfer from NCNHP to CoP could increase the electronic states of the Co d-orbital a...

Core–Shell ZIF-8@ZIF-67-Derived CoP Nanoparticle-Embedded N-Doped Carbon Nanotube Hollow Polyhedron for Efficient Overall Water Splitting

Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

Hydrogen has been hailed as a clean and sustainable alternative to finite fossil fuels in many energy systems. Water splitting is an important method for hydrogen production in high purity and large quantities. To accelerate the hydrogen evolution reaction (HER) rate, it is highly necessary to develop high efficiency catalysts and to select a proper electrolyte. Herein, the performances of non-noble metal-based carbon composites under various pH values (acid, alkaline and neutral media) for HER in terms of catalyst synthesis, structure and molecular design are systematically discussed. A detailed analysis of the structure-activity-pH correlations in the HER process gives an insight on the origin of the pH-dependence for HER, and provide guidance for future HER mechanism studies on non-noble metal-based carbon composites. Furthermore, this Review gives a fresh impetus to rational design of high-performance noble-metal-free composites catalysts and guide researchers to employ the established electrocatalysts in proper water electrolysis technologies.

Non-Noble Metal-based Carbon Composites in Hydrogen Evolution Reaction: Fundamentals to Applications.

Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Hydrogen production for energy: An overview

Hydrogen and oxygen evolution reactions (HER and OER) are important for many electrochemical systems. Besides traditional noble-metal-based catalysts, carbon-based materials have been found to be effective for catalyzing these reactions. Various carbon structures doped with heteroatoms (N, S, P, B, and transition metals) and graphitic-layer-encapsulated metal and compound particles have shown good activities toward HER and OER at universal pHs. In this Perspective, recent research on the development of carbon-based electrocatalysts for HER and OER, as well as their challenges and opportunities are discussed.

Carbon-Based Electrocatalysts for Hydrogen and Oxygen Evolution Reactions

We developed a method to engineer well-distributed dicobalt phosphide (Co2P) nanoparticles encapsulated in N,P-doped graphene (Co2P@NPG) as electrocatalysts for hydrogen evolution reaction (HER). We fabricated such nanostructure by the absorption of initiator and functional monomers, including acrylamide and phytic acid on graphene oxides, followed by UV-initiated polymerization, then by adsorption of cobalt ions and finally calcination to form N,P-doped graphene structures. Our experimental results show significantly enhanced performance for such engineered nanostructures due to the synergistic effect from nanoparticles encapsulation and nitrogen and phosphorus doping on graphene structures. The obtained Co2P@NPG modified cathode exhibits small overpotentials of only −45 mV at 1 mA cm–2, respectively, with a low Tafel slope of 58 mV dec–1 and high exchange current density of 0.21 mA cm–2 in 0.5 M H2SO4. In addition, encapsulation by N,P-doped graphene effectively prevent nanoparticle from corrosion, exhi...

Polymer-Embedded Fabrication of Co2P Nanoparticles Encapsulated in N,P-Doped Graphene for Hydrogen Generation

Recent advances in palladium-based electrocatalysts for fuel cell reactions and hydrogen evolution reaction

Nitrogen-coordinated single-metal-atom catalysts (Me–N–C) are promising candidates for CO2-to-CO electrocatalytic conversion. The nature of real active sites in this type of electrocatalyst, howeve...

Lulu Zhang

Papers

Carbon-Based Electrocatalysts for Hydrogen and Oxygen Evolution Reactions

Polymer-Embedded Fabrication of Co2P Nanoparticles Encapsulated in N,P-Doped Graphene for Hydrogen Generation

Recent advances in palladium-based electrocatalysts for fuel cell reactions and hydrogen evolution reaction

Active Sites on Heterogeneous Single-Iron-Atom Electrocatalysts in CO2 Reduction Reaction

Tuning Structural and Compositional Effects in Pd–Au Nanowires for Highly Selective and Active CO2 Electrochemical Reduction Reaction