Phase‐Controllable Growth Ni_xP_y Modified CdS@Ni₃S₂ Electrodes for Efficient Electrocatalytic and Enhanced Photoassisted Electrocatalytic Overall Water Splitting

Abstract

The rational design and construction of cost‐effective nickel‐based phosphide or sulfide (photo)electrocatalysts for hydrogen production from water splitting has sparked a huge investigation surge in recent years. Whereas, nickel phosphides (NixPy) possess more than ten stoichiometric compositions with different crystalline. Constructing NixPy with well crystalline and revealing their intrinsic catalytic mechanism at atomic/molecular levels remains a great challenge. Herein, an easy‐to‐follow phase‐controllable phosphating strategy is first proposed to prepare well crystalline NixPy (Ni3P and Ni12P5) modified CdS@Ni3S2 heterojunction electrocatalysts. It is found that Ni3P modified CdS@Ni3S2 (CdS@Ni3S2/Ni3P) exhibits remarkable stability and bifunctional electrocatalytic activities in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory results suggest that P–Ni sites and P sites in CdS@Ni3S2/Ni3P, respectively, serve as OER and HER active sites during electrocatalytic water splitting processes. Moreover, benefiting from the advantageous photocatalyst@electrocatalyst core@shell structure, CdS@Ni3S2/Ni3P delivers an advantaged photoassisted electrocatalytic water splitting property. The champion electrical to hydrogen and solar to hydrogen energy conversion efficiencies of CdS@Ni3S2/Ni3P, respectively, reach 93.35% and 4.65%. This work will provide a general guidance for synergistically using solar energy and electric energy for large‐scale H2 production from water splitting.

Ni Foam Supported TiO2 Nanorod Arrays with CdS Branches: Type II and Z‐Scheme Mechanisms Coexisted Monolithic Catalyst Film for Improved Photocatalytic H2 Production

“…According to the C–C hybrid binding energy at 284.8 eV (Figure 6D), in the calibrated Ti 2p, O 1s, Cd 3 d, and S 2p high‐resolution XPS spectra (Figure 6E–H): the binding energy peaks at around 464.3 and 458.6 eV can be, respectively, attributed to the Ti 2p 1/2 and Ti 2p 3/2 of Ti 4+ in TiO 2 ; [ 55 ] the binding energy peaks at about 530.0, 531.4, and 532.0 eV are related to the crystal lattice oxygen of Ti–O–Ti in TiO 2 and surface adsorbed water and hydroxyl groups, respectively; [ 57 ] the characteristic Cd 3d energy binding peaks located around 405.0 and 412.0 eV, together with the S 2p1/2 and S 2p2/3binding peaks at around 162.7 and 161.5 eV jointly demonstrate the presence of CdS in Ni/TiO 2 @CdS and Ni/TiO 2 @CdS‐300 samples. [ 46 ] Especially, in the Ni 2p high‐resolution spectra (Figure 6I), Ni 3+ and Ni 2+ binding energy peaks located at 875.2, 873.4, 857.6, and 855.8 eV are only found in the Ni/TiO 2 sample, which indicates that partial Ni metals are oxidized during the TiO 2 hydrothermal growth procedure. Associating with the aforementioned analysis results, it is further confirmed the content of Ni 3 S 2 in Ni/TiO 2 @CdS‐300 is very low.…”

“…Photoelectrocatalysts have been wildly applied and developed in the energy-related applications. [46] Unfortunately, to our knowledge, although attempts have been strived to construct Ni foam supporting TiO 2 systems, [37,[47][48][49][50][51][52][53][54] the direct fabrication of in situ growth vertically aligned TiO 2 nanorod arrays on Ni foam have never been reported.…”

Synthesis of NiSe2/Fe3O4 Nanotubes with Heteroepitaxy Configuration as a High‐Efficient Oxygen Evolution Electrocatalyst

“…[7,8] Therefore, it is urgent to design lowcost but efficient and stable OER electrocatalysts. To this end, transition metal-based electrocatalysts, such as oxides/hydroxides, [9][10][11][12] selenides, [13][14][15][16] sulfides, [17][18][19] and phosphides, [20,21] scheme for the synthetic approach is illustrated in Figure 1. Briefly, unique PB nanotubes are obtained by a solvothermal method, whose morphology differs from those PB polyhedrons in previous literature.…”

Defect‐Enriched ZnO/ZnS Heterostructures Derived from Hydrozincite Intermediates for Hydrogen Evolution under Visible Light

“…On the other hand, in order to improve the utilization efficiency of solar energy, the research on photocatalysts with visible light activity has become one of main research directions in the field of photocatalytic energy conversion. [11][12][13] Introducing defect engineering into heterostructure nanomaterials is an effective method to simultaneously improve their visible light properties and photocatalytic efficiency. [14][15][16] It has been demonstrated that (i) an appropriate amount of defect structures in semiconductor catalyst can be used as electron traps to capture photogenerated electrons, which can promote the effective separation of photogenerated carriers in heterostructures and improve the photocatalytic efficiency; [4,17] (ii) defect structure also benefits the formation of intermediate level and modulation of composite energy levels, which can improve the absorption and excitation of visible light.…”