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Photocatalytic evolution of hydrogen and oxygen from water splitting over semiconductors is an efficient method for solar energy conversion. In this study, the 2D/2D BiVO4−CdS heterostructures with Ti3C2Tx (Tx=O, OH, F) as a co‐catalyst were synthesized by two steps as the visible‐light‐driven photocatalysts. Compared with BiVO4 and CdS, the heterostructured catalysis exhibit greatly enhanced photocatalytic hydrogen and oxygen production performances and excellent photodegradation and photoreduction activities of methylene blue (MB) and potassium dichromate Cr(VI), respectively. The remarkable enhancement is attributed to the proposed Z‐scheme carrier transfer derived from the 2D/2D BiVO4−CdS heterostructures. Charge separation and transfer of photoexcited electrons and holes pairs are further enhanced after loading Ti3C2Tx in the BiVO4−CdS heterostructures. The potential Z‐scheme photocatalytic system and co‐catalyst endows the BiVO4−CdS−Ti3C2Tx heterostructures with strong photo‐redox capacity and excellent stability in solar energy conversion. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysts possess many advantages over single-phase catalysts. However, how to tune the heterogeneous interface state and density in heterostructures to optimize their electrocatalytic performance is still a challenge. Here, we propose a method for the preparation of NiS–NiS 2 heterostructure by vulcanization of nickel foam at high temperature, which can effectively tune the weight ratio of NiS to NiS 2 in heterostructure and their corresponding electrocatalytic urea oxidation reaction (UOR), hydrogen evolution reaction (HER) and overall urea splitting performance. The electrocatalytic activity show a trend of volcano curve with the increase of the ratio of NiS to NiS 2 , and the best electrocatalytic activity was obtained at the ratio of 6.74, in which the potentials at current density of 10 mA cm−2 of UOR, HER and overall urea splitting are 1.28 V, −49.5 mV and 1.34 V versus reversible hydrogen electrode (vs. RHE), and the Tafel slopes are 21.7, 74.1 and 90.9 mV dec−1, respectively. Furthermore, it also demonstrates excellent electrocatalytic stability. This work provides an effective way to tune the interfacial structure of heterogeneous electrocatalysts while significantly improving their electrocatalytic performance, which is beneficial to the development of efficient heterostructure and expand their applications. [Display omitted] • NiS–NiS 2 heterostructures with adjustable ratio of NiS to NiS 2 were successfully synthesized by vulcanization of nickel foam. • The electrocatalytic activity of NiS–NiS 2 show a trend of volcano curve with the increase of the ratio of NiS to NiS 2. • The NiS–NiS 2 heterostructures reveal excellent electrocatalytic activity and stability for overall urea splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] Solar-driven hydrogen evolution over ZnO-ZnS heterostructures is considered as a promising strategy for sustainable-energy issues. However, the industrialization of this strategy is still constrained by suppressed carrier migration, rapid charge recombination, and the inevitable utilization of noble-metal particles. Herein, we envision a novel strategy of successfully introducing In 2 O 3 into the ZnO-ZnS heterostructure. Benefiting from the optimized internal electric field and the charge carrier migration mode based on the direct Z-scheme, the interfacial elaborating In 2 O 3 -decorated ZnO/reduced graphene oxide (rGO)/ZnS heterostructure manifests smooth charge migration, suppressed electron–hole pair recombination, and increased surface active sites. More importantly, the in situ introduction of In 2 O 3 optimizes the construction of the internal electric field, favoring directional light-triggered carrier migration. As a result, the light-induced electrons generated from the heterostructure can be efficiently employed for the hydrogen evolution reaction. Hence, this work would shed light on the in situ fabrication of noble-metal-free photocatalysts for solar-driven water splitting. [ABSTRACT FROM AUTHOR]

Molybdenum silicides are promising electrocatalysts for hydrogen evolution in acidic environment due to their dual characteristics of metal and ceramics as well as high electrical conductivity and acid resistance. At present, most of the transition metal silicides were synthesized at high temperature, resulting in large particle size and small specific surface area, which seriously limits their electrocatalytic applications. Herein, we report a low temperature strategy for the synthesis of ultrafine Mo 5 Si 3 and MoSi 2 nanoparticles with diameter of ∼5 nm by molten salt method. Results show that both of them demonstrated excellent electrocatalytic hydrogen evolution activity and stability in 0.5 M H 2 SO 4 solution, in which the overpotentials of Mo 5 Si 3 and MoSi 2 nanoparticles at 10 mA cm−2 are 80 mV and 94 mV, respectively. This general strategy may light up the preparation of ultrafine transition metal silicides nanoparticles and facilitate their applications in electrocatalytic areas. [Display omitted] • Ultrafine Mo 5 Si 3 and MoSi 2 nanoparticles with diameter of ∼5 nm were synthesized by molten salt reduction method. • The nanoparticles demonstrate large specific surface area and fully exposed electrocatalytic active sites. • Mo 5 Si 3 show electrocatalytic HER activity in 0.5 M H 2 SO 4 with potential of −80 mV (η10) and Tafel slope of 65.1 mV dec−1. • MoSi 2 show electrocatalytic HER activity in 0.5 M H 2 SO 4 with potential of −94 mV (η10) and Tafel slope of 71.2 mV dec−1. • Mo 5 Si 3 and MoSi 2 reveal outstanding electrochemical stability for 6000 cycles of CV and 15 h of chronopotentiometry test. [ABSTRACT FROM AUTHOR]

ZnO, as a typical n-type semiconductor catalyst with low cost and high electron mobility, is concerned by numerous pursuers in the field of photocatalysis. However, because of its poor photo-reduction ability and high recombination rate, the ZnO in photocatalytic H 2 evolution is greatly limited. To acquire an outstanding photocatalytic H 2 evolution performance, 3D ordered macroporous (3DOM) ZnO is sulfurized in-situ to construct 3DOM ZnS@ZnO heterostructure. The ordered macroporous structure not only accelerates the migration of electrons and ions but also curtails the shift space of electrons and holes. The multi-junction assemblage between ZnO and ZnS effectively decreases the recombination of electron-hole pairs and improves the photo-redox capacity. The 3DOM Pt/ZnS@ZnO heterostructure exhibiting an excellent performance is 87.6 μmol g−1 h−1 in pure water. Therefore, our research presents an innovative procedure for designing other porous heterostructure photocatalysts. [Display omitted] • 3DOM ZnS@ZnO core-shell heterostructure is perfectly constructed. • The 3DOM Pt/ZnS@ZnO exhibits an improved photocatalytic H 2 evolution rate. • The ordered macroporous framework improves mass transfer efficiency. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen evolution over semiconductors is an efficient method for solar-energy conversion. Heterostructural photocatalysts with separated photoexcited carriers exhibit efficient photocatalytic hydrogen evolution without co-catalysts. In this study, heterostructures comprising of Cd 1-x Zn x S and Zn 1-y Cd y S phases were prepared through the replacement and sulfuration process at high temperature using Zn powders as the precursor. Highly crystalline Cd 1-x Zn x S-Zn 1-y Cd y S heterostructures without noble metal co-catalysts present a stable and highly effective photocatalytic hydrogen evolution rate under both UV–visible and visible-light irradiations due to the synergistic effects of Cd 1-x Zn x S and Zn 1-y Cd y S. [ABSTRACT FROM AUTHOR]

• The simultaneous evolution of H 2 and O 2 is obtained by Pt/ZnS-ZnO. • All-solid-state Z-scheme is successfully introduced into the Pt/ZnS-ZnO. • The photocatalytic reaction mechanism of the Pt/ZnS-ZnO is widely explored. The simultaneous production of the hydrogen and oxygen for photocatalytic water splitting still remains a critical challenge because O 2 release from semiconductor catalysts is an extremely difficult. Herein, we design and synthesize a novel ZnS-ZnO heterostructure sheets by combining solid-state Z-scheme for photocatalytic O 2 and H 2 evolution. Electron spin resonance result confirms that a solid-state Z-scheme is successfully introduced into the ZnS-ZnO heterostructure. Thanks to the rapid separation and migration of photoinduced electron/hole according to the Z-scheme mechanism, ZnS-ZnO heterostructure exhibits efficient H 2 evolution without using any sacrificial agent, far beyond the comparative values reported by currently ZnS/ZnO-based photocatalysts. Especially, the as-synthesized photocatalyst presents the ability of O 2 evolution for pure water splitting using Pt as cocatalyst, which is too difficult to be realized for previously reported ZnO/ZnS-based photocatalysts. Therefore, this work presents a new idea to design other semiconductor photocatalysts for simultaneous H 2 and O 2 evolution. [ABSTRACT FROM AUTHOR]