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[Display omitted] 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 AlNi 3 /NiO (Co-AlNi 3 /NiO) electrode with three-dimensional nanoporous structure via chemical dealloying method. Density functional theory (DFT) calculations reveal that Co-AlNi 3 /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 AlNi 3 , 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-AlNi 3 /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-AlNi 3 /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. [ABSTRACT FROM AUTHOR]

Atomically precise Ni 6 (SC 2 H 4 Ph) 12 nanoclusters (Ni 6 NCs) supported on g-C 3 N 4 nanosheets were constructed to enhance the photocatalytic hydrogen evolution performances. [Display omitted] Much effort has been devoted to improving the photocatalytic capacity of graphitic carbon nitride (g-C 3 N 4). In this paper, we reported the successful synthesis of a hybrid photocatalyst with superb photocatalytic hydrogen production activity through decorating atomically precise Ni 6 (SC 2 H 4 Ph) 12 nanoclusters on g-C 3 N 4 nanosheets (labeled as Ni 6 /g-C 3 N 4) at room temperature. Zeta potential experiments demonstrated that the electrostatic interaction between Ni 6 and g-C 3 N 4 led to the formation of Ni 6 /g-C 3 N 4. The photocatalytic measurements revealed that the 5 %-Ni 6 /g-C 3 N 4 prepared with the original mass ratio of m(Ni 6)/m(g-C 3 N 4) = 1/20 exhibited the strongest hydrogen production activity. In the system with triethanolamine (TEOA) as the sacrifice agent, the visible-light hydrogen production rate reached up to 5.87 mmol h−1 g−1, approximately 290 times higher than that of pure g-C 3 N 4 (0.02 mmol h−1 g−1). Density functional theory (DFT) calculations testified that the above significant enhancement of photocatalytic hydrogen evolution of the hybrid photocatalyst arose from the photogenerated electrons transfer from Ni 6 to g-C 3 N 4. [ABSTRACT FROM AUTHOR]

Sovolthermally synthesized Co-MOFs exhibits high activity and stability for water oxidation. [Display omitted] The development of efficient and robust non-precious electrocatalysts for water oxidation at a mild condition is extremely desirable for industrial water splitting. Herein we developed a facile solvothermal strategy to synthesize cobalt metal organic frameworks (Co-MOFs) with sheet-like structure, which showed highly promising performance for electrocatalytic oxygen evolution. The best Co-MOF sample afforded an ultra-high oxygen evolution current density of 63.4 mA cm−2 at 1.75 V in 1 M KOH with a catalyst loading of only 0.21 mg cm−2. Notably, its electrochemical performance remained unchanged after 10,000 cyclic voltammograms indicating very promising long-term stability. Detailed study of the mechanism of the oxygen evolution by density functional theory (DFT) indicated that the strong π-conjugation formed between the central cobalt ion and adjacent aromatic rings favored the high electrocatalytic performance. The solvothermally synthesized MOFs proposed in this paper are expected to inspire the rational design of high-performance electrocatalysts for water oxidation with atomic and molecular level structural control and the exploration of structure-performance relationships to understand the electrocatalytic origin. [ABSTRACT FROM AUTHOR]

The energy level diagram for electronic transfer vs. Vacuum level; (B and C) The photocatalytic mechanism over EY-sensitized UiO-66/WP. The abundant transition metal phosphides co-catalysts on the earth can satisfy the sustainable and clean solar H 2 production through photocatalytic water splitting, which is promising to replace the rare precious metals, such as Pt, Au, Pd, Ru and so on. In this paper, we use the temperature-programmed solid phase method to prepare WP nanoparticles. Based on the Density Functional Theory (DFT) calculations, we demonstrate that the WP nanoparticles possess outstanding electrical conductivity and excellent capability to transport electrons. WP nanoparticles are loaded onto the surface of UiO-66 via the ultrasound-assisted impregnation method to induce a highly efficient visible-light photocatalytic H 2 production activity of 384 µmol in 5 h, which is 10.67 times than that of pure UiO-66. The catalytic performance is attributed to the excellent metallic conductivity and the favourable Fermi level position of WP nanoparticles. Further studies of PL, TRPL and Mott-Schottky curves, we can not only know that the modification of WP nanoparticles do improve the electron transfer ability, but also that the matched work functions between the EY and UiO-66 provides a feasible thermodynamic path for the transmission of electrons. Our work demonstrates that the earth-abundant transition metal phosphides material have the potential to construct cheaper and high catalytic performance photocatalysts. [ABSTRACT FROM AUTHOR]