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[Display omitted] • A short-time constant potential activation strategy allows foreign ion intervention to occur in parallel with interfacial remodeling. • In situ generated Ni(Fe)OOH/NiB 4 O 7 heterostructure exposes extensive active centers and enhances the electrical conductivity by altering the charge transfer. • DFT calculations show that the presence of NiB 4 O 7 optimizes the electronic structure of the original Ni(Fe)OOH, reduces the dissociation energy barrier of H 2 O. • B 2 -NiFe-(a-10) requires only 290 mV overpotential to reach 100 mA cm−2 and can be operated stably for more than 100 h. • AEM water electrolyzer (B 2 -NiFe-(a-10) // (Pt/C)) reaches the current density of 1000 mA cm−2 at a cell voltage of 1.97 V. Self-supported NiFe-based oxygen evolution reaction (OER) catalysts with high activity and durability are essential for the industrialization of green hydrogen. Herein, Boron-interfered NiFe LDH nanosheets (B 2 -NiFe-(a-10)) with abundant wrinkle structure are prepared by introducing nonmetallic sources into the surface reconstruction of layered double hydroxide (NiFe LDH) through a novel short-time potential constant activation strategy. It enhances interactions with the electrolyte, decreases Arrhenius activation energy (Ea), accelerates efficient charge transfer and O 2 escape rate. The as-reconstructed B 2 -NiFe-(a-10) exhibits outstanding alkaline OER activity with an ultralow overpotential of 290 mV at 100 mA cm−2 and excellent durability (100 h). Additionally, density functional theory calculations further reveal that the interaction optimizes the adsorption of oxygenated intermediates (*OH→*O), induces the center of the d-band toward the Fermi energy level, and lowers the dissociation barrier of H 2 O. Moreover, the anion-exchange membrane water electrolyzer (AEMWE) achieves a current density of 1 A cm−2 at 1.97 V. [ABSTRACT FROM AUTHOR]

Three isostructural pillared-layer frameworks with M-BDC-X layers supported by ditopic HL connectors, [M(HL)(BDC)0.5X]n (HL = 4′-(4-hydroxyphenyl)-4,2′:6′,4″-terpyridine, BDC = terephthalate, M = Cd, X = Cl for (1), M = Cd, X = formate for (2), and M = Co, X = formate for (3)), were solvothermally synthesized, and used as photocatalysts for Pt-assisted visible-light-initiated hydrogen evolution from water splitting. These water-durable frameworks exhibit varied hydrogen production rates of 361.2, 271.3, and 327.5 μmol · g−1 · h−1 in 12 h due to their slightly different donor environments of the octahedral CdII and CoII ions. Further experimental and theoretical investigations reveal that the metal ions and the local coordination surroundings have essentially dominated the conduction band minimum and electric resistance of the charge transport, which play highly important roles for the improved catalytic hydrogen evolution ability. These findings demonstrate the electronic effect of the slightly ligand field modifications on the boosting hydrogen generation activity in the noble metal-assisted MOF photocatalytic systems. [ABSTRACT FROM AUTHOR]

Elucidations on the structure–activity correlations of non-Pt coordination polymer (CP)-based photocatalysts are highly significant for both the enhancement in catalytic activity and large-scale industrial applications of sustainable hydrogen from water splitting. Herein, three isostructural [Cu(HL)2(R-BDC)]n (denoted as Cu-CP-R, HL = 4′-(4-hydroxyphenyl)-4,2′:6′,4′′-terpyridine, R-BDC = 2-R-1,4-benzenedicarboxylate, R = NO2, OH and Br) CPs were solvothermally synthesized by varying the substituents attached to benzenedicarboxylate, which together with two previously reported analogues (R = NH2 and H) were used as photocatalysts to systematically explore the substitution effect on the hydrogen evolution activity. These five CPs feature isomorphic layered motifs with axially elongated CuII octahedra extended alternately by ditopic HL and R-BDC2− connectors, in which R behaves structurally as a non-coordinate group. The hydrogen production rate over the Cu-CP-R photocatalysts increased from 0.21 to 2.34 mmol g−1 h−1, which followed the order of –NH2 > –NO2 > –H > –OH > –Br. Furthermore, the combined experimental and theoretical investigations reveal that the free R moiety significantly dominates the photocatalytic activity by shifting the d states of the CuII ion towards the Fermi level, controlling the potential of the conduction band and quickening the charge transfer ability. These important findings can provide informative hints for the design of high-performance, earth-abundant non-noble metal CP-based semi-conductive photocatalysts. [ABSTRACT FROM AUTHOR]

Two copper(ii)-based layered complexes with or without the amino group, [Cu(HL)2(NH2-BDC)]n (1) and [Cu(HL)2(BDC)]n (2) (HL = 4′-(4-hydroxyphenyl)-4,2′:6′,4′′-terpyridine, NH2-H2BDC = 2-amino-1,4-benzenedicarboxylic acid and H2BDC = 1,4-benzenedicarboxylic acid), were solvothermally synthesized and used as photocatalysts to accelerate hydrogen production from water splitting. The amino group modified 1 has exhibited greatly enhanced photocatalytic activity with a hydrogen production rate of 2.34 mmol g−1 h−1 under visible light irradiation, which is almost double that of 2. Density functional theory calculations, electrochemical impedance spectroscopy and transient photocurrent tests demonstrate that the higher catalytic activity of 1 than 2 is a result of the enriched electron density around the CuII center by the amino group, which facilitates the charge transfer from the conduction band to the water molecule. [ABSTRACT FROM AUTHOR]