CDS1

Cadmium (Cd)-enriched adsorbents wastes possess great environmental risk due to their large-scale accumulation and toxicity in the natural environment. Recycling spent Cd-enriched adsorbents into efficient catalysts for advanced applications could address the environmental issues and attain the carbon neutral goal. Herein, a facile strategy is developed for the first time to reutilize the alkali lignin (AL)-derived biochar (ALB) absorbed with Cd into cadmium sulphide (CdS)/C composite for the efficient methylene blue (MB) removal. The ALB is initially treated with Cd-containing solution, then the recycling ALB samples with adsorbed Cd are converted to the final CdS/C composite using NaS₂ as the sulphurizing reagent for vulcanization reaction. The optimal ALB400 demonstrates a high adsorption capacity of 576.0 mg g^-1 for Cd removal. Then the converted CdS/C composite shows an efficient MB removal efficiency of 94%. The photodegradation mechanism is mainly attributed to carbon components in the CdS/C composite as electron acceptor promoting the separation of photoelectrons/holes and slowing down the abrasion of CdS particles. The enhanced charge transfer and contact between the carrier and the active site thus improves the removal performance and reusability. This work not only develops a method for removing Cd from wastewater effectively and achieving the waste resource utilization but also further offers a significant guidance to use other kinds of spent heavy metal removal adsorbents for the construction of low-cost and high value-added functional materials.

It is highly desirable but challenging to optimize the electronic structure of an active site to realize moderate active site-H_ads bond energies for boosting photocatalytic H₂ evolution. Herein, an interfacial engineering strategy is developed to simultaneously concentrate hydrogen species and accelerate the combination of an H_ads intermediate to generate free H₂ by constructing W-WC-W₂C (WCC) cocatalysts. Systematic investigations reveal that hybridizing with W₂C creates electron-rich W active sites and effectively induces the downshift of the d-band center of W in WC. Consequently, the strong W-H_ads bonds on the surface of WC are weakened, thus promoting the desorption of H_ads to rapidly produce free H₂. The optimized 40-WCC/CdS photocatalyst exhibits a high hydrogen evolution rate of 63.6 mmol g^-1 h^-1 under visible light (≥420 nm) with an apparent quantum efficiency of 39.5% at 425 nm monochromatic light, which is about 40-fold of the pristine CdS. This work offers insights into the design of cocatalyst for high-efficiency photocatalytic H₂ production.

Plasmonic Cu@semiconductor heteronanocrystals (HNCs) have many favorable properties, but the synthesis of solid structures is often hindered by the nanoscale Kirkendall effect. Herein, we present the use of an atomically thin Au₃Cu palisade interlayer to reduce lattice mismatch and mediate the Kirkendall effect, enabling the successive topological synthesis of Cu@Au₃Cu@Ag, Cu@Au₃Cu@Ag₂S, and further transformed solid Cu@Au₃Cu@CdS core-shell HNCs via cation exchange. The atomically thin and intact Au₃Cu palisade interlayer effectively modulates the diffusion kinetics of Cu atoms as demonstrated by experimental and theoretical investigations and simultaneously alleviates the lattice mismatch between Cu and Ag as well as Cu and CdS. The Cu@Au₃Cu@CdS HNCs feature exceptional crystallinity and atomically organized heterointerfaces between the plasmonic metal and the semiconductor. This results in the efficient plasmon-induced injection of hot electrons from Cu@Au₃Cu into the CdS shell, enabling the Cu@Au₃Cu@CdS HNCs to achieve high activity and selectivity for the photocatalytic reduction of CO₂ to CO.