Nanoporous cobalt-doped AlNi3/NiO architecture for high performing hydrogen evolution at high current densities.

Engineering platinum-free catalysts for hydrogen evolution reaction (HER) with high activity and stability is essential for electrochemical hydrogen production. In this paper, we report the synthesis of cobalt-doped AlNi3/NiO (Co-AlNi3/NiO) electrode with three-dimensional nanoporous structure via chemical dealloying method. Density functional theory (DFT) calculations reveal that Co-AlNi3/NiO can accelerate water adsorption / dissociation and optimize adsorption-desorption energies of H* intermediates, thus improving the intrinsic HER activity. Both the introduction of Co and Al can efficiently ameliorate the electronic density around Ni sites of NiO and AlNi3, which can effectively reduce the energy barrier towards Volmer-Heyrovsky reaction and thus synergistically promote the hydrogen evolution. Benefiting from the large electrochemical active surface area, high electrical conductivity and electronic effect, the nanoporous Co-AlNi3/NiO catalyst exhibits remarkable HER activity with an overpotential of 73 mV at a current density of 10 mA cm-2 in alkaline condition, outperforming most of the reported non-precious metal catalysts. The nanoporous Co-AlNi3/NiO catalyst can operate continuously over 1000 h at high current densities with a robust stability. This work provides a new vision for the development of low-cost and efficient electrocatalysts for energy conversion applications.

Dealloying-derived nanoporous Sn-doped copper with prior selectivity toward formate for CO2 electrochemical reduction.

We report nanoporous Cu-Sn catalysts fabricated by chemically dealloying rapid solidified Al-Cu-Sn alloys for the CO2RR. The np-Cu11Sn1 catalyst exhibits a three-dimensional interconnected ligament-channel network structure, which can efficiently convert CO2 to formate with a Faradaic efficiency (FE) of 72.1% at -1.0 V (vs. RHE).

Self-Supported 3 D Ultrathin Cobalt-Nickel-Boron Nanoflakes as an Efficient Electrocatalyst for the Oxygen Evolution Reaction.

The development of highly active and efficient nonprecious-metal electrocatalysts for the oxygen evolution reaction is important for the design of renewable energy production and storage devices. In this work, highly dense, ultrathin Co-Ni boride nanoflakes supported on a 3 D CoNi skeleton are fabricated in situ by a simple one-step, high-temperature, solid-state boronation process. As a result of the induced high electroactive surface area and low charge transfer resistance, CoNiB-700 exhibits high catalytic activity at an overpotential of 262 (η10 ) and 284 mV (η20 ) to deliver current densities of 10 and 20 mA cm-2 , respectively, with a Tafel slope of 58 mV dec-1 in an alkaline medium towards the oxygen evolution reaction. DFT calculations show that the Ni-regulated Co-B compound has a lower rate-determining energy barrier for the *OOH intermediate than the mono-Co-B compound, which facilitates the production of more active catalytic sites for an accelerated surface charge-transfer process for the oxygen evolution reaction.

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.