Iron, rhodium-codoped Ni2P nanosheets arrays supported on nickel foam as an efficient bifunctional electrocatalyst for overall water splitting.

To enhance the overall water splitting efficiency, it is widely attractive yet challenging to develop low price, abundance and efficient bifunctional electrocatalysts towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, Fe,Rh-codoped Ni2P nanosheets arrays were in situ anchored on three-dimension (3D) Ni foam under hydrothermal condition and successive phosphorization, denoted as Fe,Rh-Ni2P/NF for simplicity. The unique nanosheets arrays effectively enriched the active sites with easy accessibility. By virtue of the unique sheet-like arrays and 3D porous conductive substrate, the prepared Fe,Rh-Ni2P/NF showed the low overpotentials of 226 mV at 30 mA cm-2 towards the OER and 73 mV at 10 mA cm-2 for the HER. Moreover, the electrocatalyst effectively worked as anode and cathode for overall water splitting system, showing a small voltage of 1.62 V to drive a current density of 10 mA cm-2. The present work provides alternative option for fabricating advanced catalysts in electrocatalysis and energy devices.

In-situ construction of 3D hetero-structured sulfur-doped nanoflower-like FeNi LDH decorated with NiCo Prussian blue analogue cubes as efficient electrocatalysts for boosting oxygen evolution reaction.

At present, it is urgent for us to develop non-noble metal-based catalysts with abundant reserves and high efficiency towards oxygen evolution reaction (OER) in water electrolysis devices. Herein, cubic NiCo-Prussian blue analogue (PBA)/ flower-like FeNi layered double hydroxide (LDH) heterostructure was facilely in-situ formed on porous nickel foam (NF) via hydrothermal strategy coupled by subsequent sulfurizing treatment (named as S-FeNi LDH@PBA/NF), showing largely facilitated electron transfer over homogeneous counterpart. Also, we investigated the effects of different Fe/Ni feeding ratios on their catalytic properties in some detail. The as-prepared S-FeNi LDH@PBA/NF demonstrated the superior OER activity (e.g. only 243 mV of overpotential required for 50 mA cm-2) and stability. Accordingly, using the catalyst as anode, the home-assembled S-FeNi LDH@PBA/NF//Pt/C/NF electrolyzer exhibited small Tafel slope (83.1 mV dec-1) and ultra-stability, showing the potential feasibility in practical water electrolysis. This strategy provides a hopeful model to enhance the OER performance by effectively constructing advanced catalyst with promising heterostructure and optimal electronic structure.

Iron, manganese co-doped Ni3S2 nanoflowers in situ assembled by ultrathin nanosheets as a robust electrocatalyst for oxygen evolution reaction.

Exploring high-performance and stable transition metal electrocatalysts is prerequisite for boosting overall water splitting efficiency. In this study, iron (Fe), manganese (Mn) co-doped three-dimensional (3D) Ni3S2 nanoflowers were in situ assembled by many inter-connected 2D nanosheets on nickel foam (NF) via hydrothermal and sulfuration treatment. By virtue of the introduced Fe and Mn elements and unique flower-like structures, the as-prepared catalyst displayed high activity and stability for oxygen evolution reaction (OER), coupled with a small Tafel slope (63.29 mV dec-1) and a low overpotential of 216 mV to reach the current density of 30 mA cm-2. This study would shed some lights for facile synthesis of exceptional OER catalyst by tailoring the electronic structure and doping transition metal(s).

Walnut kernel-like iron-cobalt-nickel sulfide nanosheets directly grown on nickel foam: A binder-free electrocatalyst for high-efficiency oxygen evolution reaction.

Developing earth-rich and high-efficiency nonprecious metal catalysts is critical but extremely challenging for oxygen evolution reaction (OER). Herein, a simple room-temperature sulfuration method was developed for in situ synthesis of walnut kernel-like iron-cobalt-nickel sulfide nanosheets on nickel foam (FeCoNiSx/NF). The unique nanosheets exposed abundant active sites and provided large electrochemically active surface area. The as-built FeCoNiSx/NF exhibited high OER performances with the small overpotentials of 231 and 268 mV to afford 10 and 50 mA cm-2 in 1.0 M KOH, respectively, coupled with a small Tafel slope of 55 mV dec-1. Furthermore, the FeCoNiSx/NF acted as the anode towards overall water electrolysis with acceptable results, where commercial Pt/C dropped on the NF worked as the cathode. This study provides some valuable insights for rational construction of nonprecious electrocatalysts in electrochemical energy technologies.

Facile synthesis of nanoflower-like phosphorus-doped Ni3S2/CoFe2O4 arrays on nickel foam as a superior electrocatalyst for efficient oxygen evolution reaction.

Developing cost-effectiveness and superior electrocatalysts is crucial to improve the efficiency of oxygen evolution reaction (OER) in water splitting system. Hence, flower-like phosphorus doped Ni3S2/CoFe2O4 arrays (P-Ni3S2/CoFe2O4/NF) were generated on three-dimensional (3D) nickel foam (NF) via the two-step hydrothermal treatment and subsequent phosphorization. Additionally, a series of control experiments were conducted to investigate the formation mechanism. By virtue of the unique 3D configurations and multi-compositions, the as-prepared catalyst exhibited greatly improved OER performance in 1.0 M KOH solution, with the overpotential of only 254 mV at 50 mA cm-2 and low Tafel slope of 54.43 mV dec-1. This study provides a feasible approach for preparing advanced electrocatalyst in energy conversion and storage devices.

Facile synthesis of porous iridium-palladium-plumbum wire-like nanonetworks with boosted catalytic performance for hydrogen evolution reaction.

Exploring advanced nanocatalysts are of importance for hydrogen evolution reaction (HER) in alkaline electrolyte (e.g. 1.0 M KOH). Herein, porous iridium-palladium-plumbum wire-like nanonetworks (IrPdPb WNNs) were prepared by a facile one-pot aqueous method with octylphenoxypolyethoxyethanol (NP-40) as the structure-director. The resultant IrPdPb WNNs exhibited superior HER performance in the alkaline electrolyte, such as ultra-low overpotential (21 mV) to drive a current density of 10 mA cm-2, small Tafel slope (66 mV dec-1), and high exchange current density (4.87 mA cm-2), surpassing commercial Pt/C. This study provides a simple strategy for synthesis of advanced multi-metallic electrocatalysts in energy storage and conversion.

Porous dendritic PtRuPd nanospheres with enhanced catalytic activity and durability for ethylene glycol oxidation and oxygen reduction reactions.

Developing highly active and durable catalyst is of pivotal importance in fuel cells, owing to excessive consumption of fossil fuels. Herein, porous dendritic PtRuPd nanospheres (PtRuPd NSs) were synthesized by a facile hexadecylpyridinium chloride (HDPC)-mediated one-pot aqueous method with ascorbic acid (AA) as the reducing agent. The as-obtained PtRuPd NSs displayed high-efficient catalytic activity and durability for ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR). It exhibited enlarged mass activity (MA, 1.368 A mg-1) compared to commercial Pt/C (1.100 A mg-1) for EGOR. Besides, the onset potential (Eonset, 0.930 V) and half-wave potential (E1/2, 0.852 V) of PtRuPd NSs were more positive relative to homemade PtPd NSs (0.905 and 0.840 V), PdRu NSs (0.895 and 0.839 V), and commercial Pt/C (0.910 and 0.822 V) toward ORR. This work provides some valuable guidelines for producing novel trimetallic nanocatalysts in fuel cells.