Tuning Phase Structure of Nickel–Ruthenium Alloys via MOFs In Situ Hydrolysis toward Enhanced Hydrogen Evolution Performance in Alkaline

Abstract

hydrogen evolution reaction (HER). [4] Among them, metal organic frameworks (MOFs) and their derivatives have attracted wide attention thanks to their unique and designable node-ligand structure, adjustable pore structure, programmable topology structure, and so on. [5] Recently, MOFs-derived electrocatalysts such as carbon-based materials, metal (oxy)hydroxides, and multi-composition complexes have exhibited promising activity in fuel cells, refined electrosynthesis, and water splitting. [6] MOFs derived carbon-based materials through pyrolysis of MOFs contained single-atom catalysts (SACs), [7] metal nanoparticles loaded carbon materials (M-NPs/C), carbon coating metal oxides, carbide, sulfide, or phosphide materials (MO x /C, MC x /C, MS x /C, and MP x /C). [8] Researchers have developed various strategies for synthesizing MOFs-derived SACs such as Ru-SACs, Ni-SACs, Pt-SACs and Co-SACs, and investigating their activity toward water splitting. [9] Even more, dual-metal SACs and single atom/cluster materials were reported subsequently via ration atomic-scale engineering in MOFs precursor. John Wang et al. proposed a cage-confinement pyrolysis approach of zeolitic imidazolate frameworks (ZIFs) confining molybdenum-based polyoxometalate precursor to synthesize size-controlled Mo-based carbon materials, including Mo-SACs, MoC/C, or Mo-NPs/C. [10] Under different pyrolysis experimental parameters, Mo species showed diverse aggregation behavior, from single atoms to nanoclusters and nanoparticles. Meanwhile, the production of MO x /C, MS x /C or MP x /C is dependent on the addition of another nonmetal source during the pyrolysis process, such as oxygen gas, sulfur powder, and NaH 2 PO 4 , respectively. [11] During the aforementioned oxidation, sulfuration, or phosphorization process, hierarchical pore structure, and hollow structure could be constructed artificially to satisfy mass transport and facilitate proton-electron coupling reaction.In decades, hydrolysis reaction of MOFs was proposed, where MOFs played the role of sacrificial templates. Chen et al. first reported hydrolysis factors (e.g., pH and cation ratio) and synthesized serial MOFs-derived metal hydroxides (M x (OH) y ) dodecahedron. [12] MOFs-derived M x (OH) y via hydrolysis reaction, in particular, typically expose more active sites owing to the generation of cross-scale pores during topological Metal organic frameworks (MOFs) and corresponding derivatives have attracted wide attention. As electrocatalysts, these derivatives (metal, metal compound, and associated composites) have a wide range of application in water-splitting devices, fuel cells, and other hydrogen-related technologies. However, with the exception of pyrolysis, limited studies have documented generated metal nanoparticles from MOFs hydrolysis reactions. Herein, NiRu dual-phase alloy nanoparticles are synthesized via in situ MOFs hydrolysis mediating solvothermal reduction reaction. The hcp-phase NiRu alloys can be rationally tuned by modulating experimental parameters of feedin...

Heterostructure Interface Engineering in CoP/FeP/CeOx with a Tailored d-Band Center for Promising Overall Water Splitting Electrocatalysis

“…To further disclose the insight into the electrocatalytic enhancement, the valence band spectra of the different samples were measured by XPS and experimentally quantified as the d-band center by subtracting the valence band spectrum from the background via a Shirley-type baseline. The original data are shown in Figure S20. − As shown in Figure c, regardless of the modulated Co/Fe ratio or the introduction of Ce, Co3Fe/Ce0.025 exhibited the lowest d-band center position of 7.35 eV. The d-band center positions of the other samples are closer to the Fermi level and they own stronger adsorption ability, leading to a slow desorption process during the catalytic reaction and therefore hindering the reaction .…”

Hollow Starlike Ag/CoMo-LDH Heterojunction with a Tunable d-Band Center for Boosting Oxygen Evolution Reaction Electrocatalysis

“…In order to gain deeper insight into the enhancement of electrocatalytic activity, X-ray photoelectron spectroscopy (XPS) was used to measure the valence band spectra of the different samples (SI eq S1). The d-band center was experimentally quantified by subtracting the valence band spectrum from the background using a Shirley-type baseline, allowing for a detailed analysis of the electrocatalytic properties. , Figure c displays the XPS valence band spectra of pure CoMo-LDH and catalysts with varying amounts of Ag. It was observed that Ag0.4/CoMo-LDH exhibited the lowest d-band center, measuring 5.65 eV.…”

“…The d-band center was experimentally quantified by subtracting the valence band spectrum from the background using a Shirley-type baseline, allowing for a detailed analysis of the electrocatalytic properties. 64,65 Figure 5c displays the XPS valence band spectra of pure CoMo-LDH and catalysts with varying amounts of Ag. It was observed that Ag0.4/CoMo-LDH exhibited the lowest d-band center, measuring 5.65 eV.…”

Design and Synthesis of Noble Metal‐Based Alloy Electrocatalysts and Their Application in Hydrogen Evolution Reaction

“…Meng et al. [ 68 ] obtained NiRu alloys by hydrolysis of Ni metal‐organic frameworks (MOFs) in the presence of Ru 3+ by the solvothermal method. The timing of Ru 3+ addition affects the phase of the final alloy obtained.…”