Sequential Chemistry Toward Core–Shell Structured Metal Sulfides as Stable and Highly Efficient Visible‐Light Photocatalysts

Uniform H-CdS@NiCoP core-shell nanosphere for highly efficient visible-light-driven photocatalytic H2 evolution

Constructing highly efficient and cost-effective photocatalyst system has been a big challenge for photocatalysis. Herein, CdS nanosphere (N-CdS), hollow CdS (H-CdS) and a series of H-CdS@NiCoP core-shell nanospheres have been successfully prepared via a facile hydrothermal method. The activity test showed that H-CdS exhibited higher photocatalytic activity (3.34 mmol g^-1h^-1) compared with N-CdS (0.99 mmol g^-1h^-1) under visible light irradiation (λ ≥ 420 nm), suggesting that hollow structure could effectively improve photocatalytic activity. Moreover, the H-CdS@NiCoP-7 wt% displayed a maximum photocatalytic H₂ evolution rate of 13.47 mmol g^-1h^-1, which was about 4 times and 2.5 times higher than that of pristine H-CdS and H-CdS@Pt-3 wt%, respectively. Furthermore, H-CdS@NiCoP-7 wt% exhibited a good stability during 20 h test. The physicochemical properties were characterized by XRD, SEM, TEM, XPS, UV-vis DRS, PL and photoelectrochemical technique. The results showed that NiCoP addition can construct p-n junction with H-CdS and effectively promote the charge transfer from CdS to NiCoP, which improved the photocatalytic hydrogen evolution activity. This work revealed that NiCoP could react as an excellent co-catalyst for enhancing H-CdS photocatalytic activity.

Photocatalytic H2O Overall Splitting into H2 Bubbles by Single Atomic Sulfur Vacancy CdS with Spin Polarization Electric Field

Low efficient transfer of photogenerated charge carriers to redox sites along with high surface reaction barrier is a bottleneck problem of photocatalytic H₂O overall splitting. Here, in the absence of cocatalysts, H₂O overall splitting has been achieved by single-atomic S vacancy hexagonal CdS with a spin polarization electric field (PEF). Theoretical and experimental results confirm that single-atomic S vacancy-induced spin PEF with opposite direction to the Coulomb field accelerates charge carrier transport dynamics from the bulk phase to surface-redox sites. By systematically tuning the spin PEF intensity with single-atomic S vacancy content, common pristine CdS is converted to a photocatalyst that can efficiently complete H₂O overall splitting by releasing a great number of H₂ bubbles under natural solar light. This work solves the bottleneck of solar energy conversion in essence by single atom vacancy engineering, which will promote significant photocatalytic performance enhancement for commercialization.