Electrocatalytic activity of CO2 reduction to CO on cadmium sulfide enhanced by chloride anion doping

The electrocatalytic CO2 reduction (ECR) to produce valuable fuel is a promising process for addressing atmospheric CO2 emissions and energy shortages. In this study, Cl-anion doped cadmium sulfide structures were directly fabricated on a nickel foam surface (Cl/CdS-NF) using an in situ hydrothermal method. The Cl-anion doping could significantly improve ECR activity for CO production in ionic liquid and acetonitrile mixed solution, compared to pristine CdS. The highest Faradaic efficiency of CO is 98.1 % on a Cl/CdS-NF-2 cathode with an excellent current density of 137.0 mA cm-2 at -2.25 V versus ferrocene/ferrocenium (Fc/Fc+ , all potentials are versus Fc/Fc+ in this study). In particular, CO Faradaic efficiencies remained above 80 % in a wide potential range of -2.05 V to -2.45 V and a maximum partial current density (192.6 mA cm-2 ) was achieved at -2.35 V. The Cl/CdS-NF-2, with appropriate Cl anions, displayed abundant active sites and a suitable electronic structure, resulting in outstanding ECR activity. Density functional theory calculations further demonstrated that Cl/CdS is beneficial for increasing the adsorption capacities of *COOH and *H, which can enhance the activity of the ECR toward CO and suppress the hydrogen evolution reaction.

Extraterrestrial artificial photosynthetic materials for in-situ resource utilization

Aerospace milestones in human history, including returning to the moon and manned Martian missions, have been implemented in recent years. Space exploration has become one of the global common goals, and to ensure the survival and development of human beings in the extraterrestrial extreme environment has been becoming the basic ability and technology of manned space exploration. For the purpose of fulfilling the goal of extraterrestrial survival, researchers in Nanjing University and the China Academy of Space Technology proposed extraterrestrial artificial photosynthesis (EAP) technology. By simulating the natural photosynthesis of green plants on the Earth, EAP converts CO2/H2O into fuel and O2 in an in-situ, accelerated and controllable manner by using waste CO2 in the confined space of spacecraft, or abundant CO2 resources in extraterrestrial celestial environments, e.g. Mars. Thus, the material loading of manned spacecraft can be greatly reduced to support affordable and sustainable deep space exploration. In this paper, EAP technology is compared with existing methods of converting CO2/H2O into fuel and O2 in the aerospace field, especially the Sabatier method and Bosch reduction method. The research progress of possible EAP materials for in-situ utilization of extraterrestrial resources are also discussed in depth. Finally, this review lists the challenges that the EAP process may encounter, which need to be focused on for future implementation and application. We expect to deepen the understanding of artificial photosynthetic materials and technologies, and aim to strongly support the development of manned spaceflight.

Two dimensional Ni2P/CdS photocatalyst for boosting hydrogen production under visible light irradiation

Two-dimensional (2D) semiconductor materials have attracted considerable attention in the field of photocatalysis due to the high interfacial charge separation efficiency and abundant surface active sites. Herein, we have fabricated 2D/2D sheets of Ni2P/CdS heterostructure for photocatalytic H2 evolution. The microscopic and photocatalytic activity results suggested that Ni2P nanosheets were coupled with snowflake CdS. The optimal hydrogen production rate reached 58.33 mmol h-1 g-1 (QE = 34.38%, λ = 420 nm) over 5 wt% Ni2P, which is equivalent to that of 1 wt% Pt/CdS. Compared with pure CdS, Ni2P/CdS presented lower fluorescence intensity and stronger photocurrent density, which demonstrated that the 2D/2D Ni2P/CdS heterojunction photocatalyst significantly improved the separation efficiency of photogenerated electrons and holes. The excellent performance of Ni2P/CdS clearly indicated that Ni2P was an excellent cocatalyst and could provide abundant active sites for hydrogen evolution.

Coupling the fluorescence and adsorptive properties of biomass-based cellulose–CdS nanocomposite for the alleviation of water contaminants

Integration of CdS nanoparticles with CNF nanofibers for selective fluorescence detection of pharmaceutical waste and adsorptive elimination of textile and pesticide waste.

Mesoporous CdxZn1-xS with abundant surface defects for efficient photocatalytic hydrogen production

The practical application of photocatalytic water splitting for hydrogen evolution hinges on the development of high-efficient and low-cost photocatalysts. Defects engineering has emerged as a promising strategy to enhance photocatalytic activity effectively. Herein, a facile and versatile co-precipitation method is proposed to fabricate mesoporous Cd-Zn-S solid solutions (E-Cd_xZn_1-xS) with abundant surface defects by the inorganic salts formed in the reaction system as self-template. Compared with Cd-Zn-S solid solutions (W-Cd_0.65Zn_0.35S) prepared by the traditional co-precipitation method, the enhanced specific surface area and abundant surface defects endow E-Cd_0.65Zn_0.35S with more accessible active sites and effective separation of electron-hole pairs for the photocatalytic water splitting reaction. The E-Cd_0.65Zn_0.35S solid solution exhibits hydrogen evolution rate of 5.2 mmol h^-1 g^-1 without loading noble metal as cocatalyst under visible light, which is 1.13 times higher than that of W-Cd_0.65Zn_0.35S sample. The present work provides a simple, low-cost and prospective strategy for the synthesis of defective Cd-Zn-S solid solutions, and it also delivers guidance to design and develop the advanced visible-light photocatalyst in the future.