Oxygen-vacancy-rich MoO2 supported nickel as electrocatalysts to promote alkaline hydrogen evolution and oxidation reactions

Synergistic Promotion of Large‐Current Water Splitting through Interfacial Engineering of Hierarchically Structured CoP−FeP Nanosheets with Rich P Vacancies

“…As shown in Figure 3e, exchange current density (j 0 ) was obtained by extrapolating Tafel slope to measure intrinsic HER catalytic activity of materials. [32] The j 0 value of VpÀ CoPÀ FeP/NF (1.51 mA cm À 2 ) was higher than that of other comparative catalysts except Pt/C/NF, indicating that VpÀ CoPÀ FeP/NF can make electrode reaction easier and electron transfer faster. The Nyquist plots (Figure 3f) showed that VpÀ CoPÀ FeP/NF had smaller charge-transfer resistance (R ct ) approaching that of Pt/C/NF, revealing its stronger electron transfer capability, higher conductivity and faster reaction kinetics.…”

Constructing Symmetry-Mismatched RuxFe3–xO4 Heterointerface-Supported Ru Clusters for Efficient Hydrogen Evolution and Oxidation Reactions

“…57 Fe Mössbauer spectroscopy further verified the higher contents of Fe 2+ and Fe 2.5+ in Ru/Ru x Fe 3– x O 4 , compared with the presence of abundant Fe 3+ in Fe 3– x O 4 (Figure c and Table S2), indicating that heteroatom doping resulted in a greater degree of unsaturated coordination. , The dominating Ru atoms are mainly in the metallic state, while the presence of Ru 4+ is due to the formation of the Ru–O bond (Figure c). , Then it can be postulated that weak Ru atom doping infiltrates Fe 3– x O 4 and facilitates the formation of bonds, which is reinforced by the findings from electron microscopy. The O 1s spectrum (Figure S9) shows the rich M–O–M bond, which proves the formation of Ru/Fe(Ru)O x heterogeneous interfaces . More unsaturated sites for reactions were provided through the symmetry-breaking process, resulting in more oxygen vacancies .…”

“…The O 1s spectrum (Figure S9) shows the rich M−O−M bond, which proves the formation of Ru/ Fe(Ru)O x heterogeneous interfaces. 46 More unsaturated sites for reactions were provided through the symmetry-breaking process, resulting in more oxygen vacancies. 46 Moreover, electron paramagnetic resonance (EPR) analysis further confirms the existence of oxygen vacancies, which possess the amount of unpaired electrons that can stabilize Ru clusters in Ru/Ru x Fe 3−x O 4 (Figure S10).…”

“…46 More unsaturated sites for reactions were provided through the symmetry-breaking process, resulting in more oxygen vacancies. 46 Moreover, electron paramagnetic resonance (EPR) analysis further confirms the existence of oxygen vacancies, which possess the amount of unpaired electrons that can stabilize Ru clusters in Ru/Ru x Fe 3−x O 4 (Figure S10). 47 The increase in the oxygen vacancy content of Ru/Ru 43 The valence state and local coordination structure of Ru/ Ru x Fe 3−x O 4 were investigated using X-ray absorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy.…”

Heterogeneous Co–Ni phosphide with active sites for water dissociation and efficient hydrogen evolution reaction

“…Transition metal phosphides (TMPs), such as CoP, Ni 2 P, and MoP, have attracted a great deal of attention for supporting hydrogen generation in recent decades. 9–12 In particular, bimetallic phosphide NiCoP is considered an ideal material to replace commercial platinum-based catalysts because of its high catalytic activity. 13,14 For example, Wang and co-workers 15 found that bimetallic NiCoP nanosheets exhibited improved HER activity compared with that of the corresponding monometallic phosphides Ni 2 P and CoP.…”