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The ethanol oxidation reaction (EOR) is an ideal alternative to the oxygen evolution reaction (OER) towards energy efficient hydrogen production. Here, the chrysanthemum-shaped B doped cobalt-nickel bimetallic phosphide with heterogeneous structure grown on nickel foam (B-Ni 2 P/CoP/NF) are synthesized and can act as a high activity bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and EOR. In 1.0 M KOH, the obtained catalyst shows good activity and excellent long-term stability (no decay after 108 h) for HER, with an overpotential of only 33 mV (vs. RHE) to reach a current density of 10 mA cm−2. The calculation of turnover frequency (TOF) and transfer coefficient (β) prove that the catalyst has good intrinsic catalytic activity, For EOR, in 1.0 M KOH+1.0 M C 2 H 5 OH solution, the B-Ni 2 P/CoP/NF catalyst requires only 1.45 V (vs. RHE) oxidation potential to reach the current density of 50 mA cm−2, which is 270 mV less than OER. Using B-Ni 2 P/CoP/NF as a bifunctional catalyst, the current density of 20 mA cm−2 can be achieved with only 1.48 V cell voltage in 1.0 M KOH+ 1.0 M C 2 H 5 OH solution, which is remarkably lower than the required cell voltage of water electrolysis (1.63 V) to achieve the same current density. This study demonstrates an efficient bimetallic phosphide as earth-abundant bifunctional electrocatalysts for green hydrogen production coupled with electrolysis of ethanol. [Display omitted] • The chrysanthemum-shaped B-CoP/Ni 2 P/NF catalyst with heterogeneous structure is prepared. • The B-CoP/Ni 2 P/NF catalyst has excellent bifunctional catalytic activity toward EOR and HER.in alkaline solution. • The doping of B regulates the electronic structure and further strengthens the synergistic effect of metal Ni and Co. [ABSTRACT FROM AUTHOR]

The development of renewable clean energy is imminent as global warming and environmental pollution become more serious issues today. Hydrogen energy has been widely studied as an ideal green energy source. Among several common hydrogen production methods, hydrogen production by electrolysis of water is considered an efficient, environmentally friendly, and sustainable hydrogen production strategy. Transition metal phosphates have outstanding electrocatalytic conductivity and high catalytic efficiency, thus exhibiting catalytic effects similar to noble metals. To further enhance the catalytic activity of the transition metal phosphates, in this paper, the cauliflower-like Co-W-P-O 4 /NF catalyst based on three-dimensional nickel foam was prepared by the method of element doping. The catalyst exhibited good bifunctional catalytic activity in alkaline solution. The prepared Co-W-P-O 4 /NF has a unique crystalline-amorphous phase structure with abundant active sites at the interface. In addition, W atoms can interact with Co atoms to co-optimise the electronic structure, enabling the Gibbs free energy of hydrogen adsorption (ΔG H*) to be close to 0, which is conducive to improving the performance of water electrolysis. To achieve a current density of 10 mA·cm−2, the Co-W-P-O 4 /NF required overpotentials of 42.1 mV for HER and 348.2 mV for OER in 1 M KOH solution, with the Tafel slopes being 48.0 and 83.6 mV·dec−1, respectively. When Co-W-P-O 4 /NF was used as both cathode and anode for water splitting, the two-electrode electrolyzer could achieve 10 mA·cm−2 with only 1.62 V, along with good stability. [Display omitted] • The cauliflower-like Co-W-P-O 4 /NF with crystalline-amorphous phase structure is prepared. • Co-W-P-O 4 /NF catalyst shows good bifunctional catalytic activity in alkaline solution. • The electron rearrangement and the rough surface structure can improve the performance of catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Grape cluster Cu-Co-P/NF was prepared by one-step potentiostatic electrodeposition. • Cu-Co-P/NF exhibit excellent catalytic activity and high stability for HER and OER. • The moderate amount of Cu doping could tune the electronic structure. The application of non-precious metal bifunctional electrode materials is relevant to solving the current serious energy and environmental problems. In this study, the Cu-Co-P/NF bifunctional electrocatalyst with grape-like clusters was successfully prepared for water splitting using nickel foam (NF) as a substrate by electrodeposition. In alkaline conditions, the catalysts showed good catalytic activity and stability in both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). At 10 mA cm-2, the overpotential required for HER was only 64 mV, whereas for OER it was 334 mV, with Tafel slopes of 40 mV dec-1 and 74 mVdec-1, respectively, and almost negligible potential fluctuations after 49 h and 52 h of testing under continuous electrolysis. Furthermore, the two-electrode electrolyzer required only 1.55 V to achieve 10 mA cm-2 in 1 M KOH solution when Cu-Co-P/NF was used as both cathode and anode for water splitting, which was superior to most previously reported electrocatalysts, and it also showed good durability in a 82 h test. Therefore, it has promising applications in industrial electrolytic systems. The unusual Cu-Co-P/NF with grape-like clusters, as well as the synergistic effect between Co and Cu atoms and the high electrochemically active surface area (ECSA), are responsible for the remarkable catalytic performance. [ABSTRACT FROM AUTHOR]