Bimetallic Cu-Co-Se Nanotube Arrays Assembled on 3D Framework: an Efficient Bifunctional Electrocatalyst for Overall Water Splitting.

Highly active bifunctional electrocatalysts for water splitting are of particular importance for the widespread usage of renewable energy, which require synergistic effect of ingenious architecture and intrinsic catalytic activity. Herein, a novel Cu-Co-Se nanotube array supported on 3D copper skeleton was synthesized as high-efficiency bifunctional electrocatalyst for overall water splitting via a facile two-step hydrothermal method. The rationally designed Cu-Co-Se nanotube electrocatalyst exhibited good electrocatalytic performance, with overpotential of only 152 mV to generate 10 mA cm-2 for the hydrogen evolution reaction and a small overpotential of 332 mV to drive a current density of 50 mA cm-2 for the oxygen evolution reaction. The good electrocatalytic performance was mainly due to the large electrochemical surface area and electronic coupling synergies triggered by the self-supported bimetallic nanotube architecture. The water splitting system assembled using Cu-Co-Se nanotube as cathode and anode only needed a cell voltage of 1.65 V to drive a current density of 10 mA cm-2 with long durability of 50 h for overall water splitting. Furthermore, density functional theory calculations proved that the existence of electron exchange between the neighboring bimetals as well as the coupling between Cu, Co, and Se contributed to the improvement of the water splitting performance. This work provides a general strategy to develop cost-efficient and geometrically superior bimetallic electrocatalysts toward water splitting for large-scale hydrogen production.

Hybrid Ni3S2-MoS2 nanowire arrays as a pH-universal catalyst for accelerating the hydrogen evolution reaction.

Hybrid Ni3S2-MoS2 NWAs/NF, hybrid Ni3S2-MoS2 nanowire arrays in situ grown on Ni foam via a two-step hydrothermal method, can achieve cathodic current densities of 10 mA cm-2 and 100 mA cm-2 at overpotentials of 99 mV and 260 mV in 1.0 M KOH and 111 mV and 194 mV in 0.5 M H2SO4, respectively. It still needs an overpotential of 103 mV at 10 mA cm-2 in 0.1 M PBS. This work opens a new avenue for designing heterogeneous active electrocatalysts for energy conversion and storage.

Facile synthesis, characterization and DFT studies of a nanostructured nickel-molybdenum-phosphorous planar electrode as an active electrocatalyst for the hydrogen evolution reaction.

In this paper, we combined experimental and theoretical routes to develop a novel nanostructured nickel-molybdenum-phosphorous planar electrode as an efficient catalyst toward the hydrogen evolution reaction (HER). The HER activities of various Ni-based electrodes (Ni4Mo and Ni12P5) were evaluated not only experimentally but also by density functional theory. Meanwhile, the electrocatalytic performance of Ni-Mo-P prepared at different temperatures (500 °C, 600 °C, 700 °C, and 800 °C) was also explored. The results indicated that the sample prepared at 700 °C exhibited the best catalytic activity. The as-fabricated Ni-Mo-P electrode possessed lower overpotential, higher current density and a smaller Tafel slope than pristine modified Ni@Ni-Mo in 1.0 M KOH and also showed long-term stability. An overpotential as low as 276 mV could be achieved at 100 mA cm-2 H2 evolving current density, which was superior to those of most previously reported samples. After phosphorization treatment, the as-formed Ni12P5 played a crucial role in the activity enhancement. Density functional theory calculations revealed that Ni12P5 has a smaller |ΔGH*| value than Ni4Mo, further confirming that Ni12P5 shows better catalytic performance than Ni4Mo.