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Using non-toxic red phosphorus as the phosphorus source, Ni 2 P was synthesized and in situ loaded on Cd 0.5 Zn 0.5 S photocatalyst by a simple solvothermal method for photocatalytic H 2 evolution under visible light (λ ≥ 420 nm) irradiation. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS), Brunauer–Emmett–Teller (BET) surface area measurements and electrochemistry techniques. The photocatalytic hydrogen evolution activity over Cd 0.5 Zn 0.5 S is significantly increased by in situ-loaded Ni 2 P due to the intimate interface contact and efficient charge transfer from Cd 0.5 Zn 0.5 S to Ni 2 P. The 4 wt%Ni 2 P-loaded Cd 0.5 Zn 0.5 S photocatalyst shows five times higher H 2 evolution rate than that of the pristine Cd 0.5 Zn 0.5 S. The highest H 2 evolution rate of 65.6 μmol/h and the apparent quantum yield (AQY) of 29% at 420 nm is achieved under the optimized conditions. The noble metal free Ni 2 P is stable during 20 h photocatalytic reaction. [ABSTRACT FROM AUTHOR]

A series of ZIS-x [ZIS and x represent the ZnIn 2 S 4 and the addition amount of TEOA (mmol) in the synthesis process, respectively] were synthesized via a hydrothermal method using triethanolamine (TEOA) as a template. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Ultraviolet-visible (UV–vis) diffuse reflection spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement. The effects of TEOA on the crystal structures, morphologies and optical properties of ZIS-x products were investigated. The photocatalytic activity was tested in the reaction of H 2 evolution from aqueous TEOA solution under visible light irradiation (λ ≥ 420 nm). It was found that the activity of ZIS-x synthesized in TEOA solution was higher than that of ZIS-0 synthesized in pure water. This can be attributed to the facts that ZIS-x is composed of single ZnIn 2 S 4 and more TEOA can be adsorbed on ZIS-x surface, which improves the separation of an electron-hole pair. When TEOA was used as an electron donor, it can enhance notably photocatalytic H 2 evolution with its simultaneous degradation. The effect of TEOA concentration on the H 2 evolution rate is consistent with a Langmuir–Hinshelwood kinetic model. The optimal amount of Pt loaded on the photocatalyst is 0.50 wt%, and the optimal pH for photocatalytic H 2 evolution is 13. On the optimal condition, the rate of hydrogen evolution over ZIS-2.0 is 2 times as high as that of ZIS-0 during 20 h irradiation. [ABSTRACT FROM AUTHOR]

Nickel species were loaded on titanate nanotubes (TNT) as a hydrogen evolution cocatalyst by an impregnation–calcination method. Nickel chloride, nickel nitrate and nickel acetate were used as the precursors. More Ni 2+ ions intercalate into the interlayer of TNT when nickel chloride is used as the precursor. In the calcination process, the titanate transforms into anatase TiO 2 , and Ni 2+ ions are reduced and doped partly in TiO 2 and titanate. The Ni 2+ ions intercalated into TNT inner can promote the phase transformation, growth of metal Ni particles and the Ni 2+ doping. The formed Ni particles can be oxidized in air to form core/shell Ni@NiO structure. The Ni 2+ doping promotes the formation of oxygen defects and increases the conductivity of TNT. The photocatalytic activity of Eosin Y-sensitized nickel-modified TNT for hydrogen evolution was investigated. The TNT modified with nickel chloride exhibit higher activity, which can be attributed to the higher conductivity and more effective formation of Ni@NiO structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni 12 P 5 was in situ anchored on ZnIn 2 S 4 via a solvothermal route. • The intimate interface between Ni 12 P 5 and ZnIn 2 S 4 can promote the charge transfer from ZnIn 2 S 4 to Ni 12 P 5. • ZnIn 2 S 4 loaded with 6 wt% Ni 12 P 5 exhibits the best hydrogen production activity and excellent stability. • The possible photocatalytic mechanism was discussed. It is a great challenge to develop efficient, stable and inexpensive hydrogen evolution reaction (HER) catalysts for photocatalytic water-splitting. In this paper, Ni 12 P 5 (NP) was in situ anchored on the surface of ZnIn 2 S 4 (ZIS) via a solvothermal route with nickel chloride and red phosphorus as ingredients. Using triethanolamine as sacrificial agent, the photocatalytic hydrogen evolution activity of NP/ZIS was studied under visible light irradiation. At the same time, the composition, structure, morphology and photoelectrochemical properties of the as-obtained samples were analyzed through a sequence of characterization techniques. ZIS loaded with 6 wt% NP (6NP/ZIS) exhibits the best hydrogen evolution activity and excellent stability. The H 2 evolution rate of 6NP/ZIS is 5.4 times higher than that of pristine ZIS and well beyond that of the physical mixture (6NP + ZIS) or even that of the optimal Pt/ZIS under the same conditions. The maximal apparent quantum yield (AQY) of 22.7 % at 400 nm is achieved, superior to the most reported performance of ZnIn 2 S 4 -based photocatalysts for HER. The anchor of NP can not only enhance the visible light absorption intensity, but also reduce the HER overpotential. More importantly, the intimate interface between ZIS and NP can promote the separation and migration of photo-excited carriers, thereby enhancing the activity of photocatalytic hydrogen evolution. The possible photocatalytic reaction mechanism was discussed. [ABSTRACT FROM AUTHOR]

It remains a challenge to develop efficient and inexpensive catalysts for hydrogen evolution reaction (HER). Herein, it is the first time to report a core-shell structured amorphous Fe-B alloy coupled with metal Fe nanoclusters as an efficient HER catalyst. The composite was fabricated via the transformation of the FeOOH coating on amorphous Fe-B alloy into metal Fe through a simple photoreduction approach. The Fe nanoclusters loaded on amorphous Fe-B alloy improve the catalytic HER. Thus, the as-prepared composite exhibits much better electrocatalytic and photocatalytic HER activities than single Fe and Fe-B alloy, that is, there is a synergic effect between Fe metal and amorphous Fe-B alloy. The highest apparent quantum yield (AQY) for photocatalytic HER reaches 34% at 470 nm with Eosin Y as a photosensitizer. The composite cocatalyst can be recovered by a magnetic field after the dye-sensitized photocatalytic HER. More interestingly, the electrocatalytic HER activity of Fe-B@Fe-10 in alkaline solution surpasses that of foam Ni used in industrial water electrolysis, and the core-shell composite shows excellent HER performance at high current density. The findings provide new insights to develop efficient and stable noble-metal-free HER catalysts. [ABSTRACT FROM AUTHOR]

• Ni-B coupled with borate-intercalated Ni(OH) 2 as a novel HER catalyst in alkaline system. • Intercalated borate enhances electro- and photo-catalytic HER activity and stability of the composite. • Interlayer borate improves proton transport from Ni(OH) 2 to Ni-B and stabilizes Ni(OH) 2. • This work provides new insights for design new composite HER catalysts at alkalinity. To convert solar energy into storable chemical fuel hydrogen via water splitting, it is highly required to develop efficient, low-cost and stable HER (hydrogen evolution reaction) catalysts and systems. For practical application, the HER catalysts can work in low alkaline or neutral reaction systems. However, in these reaction systems, water dissociation into proton is a rate-determining step, which can be overcome by loading metal oxide or hydroxides onto the HER catalysts. Ni(OH) 2 is a well-reported cocatalyst to assist water dissociation. Herein, Ni-B@Ni(OH) 2 [Ni-B with loaded Ni(OH) 2 as a HER catalyst at weak alkalinity has been investigated. Very interestingly, we find that when borate is added into the above reaction systems, the resultant catalyst Ni-B@Ni(OH) 2 -BI shows much better HER activity and stability than Ni-B@Ni(OH) 2. The reason is that borate ions can intercalate into Ni(OH) 2 interlayers, which increases proton transport ability and stability of Ni(OH) 2 loaded on Ni-B. These findings provide new insights for design new composite catalysts of HER in low alkaline reaction systems. [ABSTRACT FROM AUTHOR]