Silver nanoparticles (Ag NPs) supported on certain materials have been widely used as disinfectants. Yet, to date, the antibacterial activity of the supported Ag NPs is still far below optimum. This is mainly associated with the easy aggregation of Ag NPs on the supporting materials. Herein, an electron-assisted reduction (EAR) method, which is operated at temperatures as low as room temperature and without using any reduction reagent, was employed for immobilizing highly dispersed Ag NPs on aminated-CNTs (Ag/A-CNTs). The average Ag NPs size on the EAR-prepared Ag/A-CNTs is only 3.8 nm, which is much smaller than that on the Ag/A-CNTs fabricated from the traditional thermal calcination (25.5 nm). Compared with Ag/A-CNTs fabricated from traditional thermal calcination, EAR-prepared Ag/A-CNTs shows a much better antibacterial activity to E. coli/S. aureus and antifouling performance to P. subcordiformis/T. lepidoptera. This is mainly originated from the significantly enhanced Ag+ ion releasing rate and highly dispersed Ag NPs with small size on the EAR-prepared Ag/A-CNTs. The findings from the present work are helpful for fabricating supported Ag NPs with small size and high dispersion for efficient antibacterial process.

•Coconut shell nanocarbon (CSC) prepared for photocatalysis of H2 production.•A H2 evolution rate as high as 1679.5 μmol h−1.•Abundant nanopores and surface oxygen-containing groups on CSC.•CSC facilitating electron transfer kinetics.•CSC promoting separation of the photoinduced electron–hole pairs.Coconut shell carbon (CSC) nanosheets were applied to support CdS quantum dots (≤5 nm) and Pt nanoparticles to form a composite Pt/CdS/CSC catalyst for the visible-light-driven photocatalytic H2 production from water. The H2 evolution rate on Pt/CdS/CSC is as high as 1679.5 μmol h−1, which is significantly enhanced as compared with that on Pt/CdS without CSC (636.2 μmol h−1). Electrocatalytic experiments indicate a highly efficient electron transfer on the CSC nanosheets, which may be due to the presence of the abundant nanopores (<4 nm) and surface oxygen-containing groups behaving as the charge capture traps. The unique electron transfer flexibility of CSC facilitates the separation of the photoinduced electron–hole pairs on CdS/Pt/CSC in the photocatalytic process. This is the main origin for the significantly enhanced photocatalytic performance of CdS/Pt/CSC. It is believed that the findings from this study will provide useful clues for designing efficient biochar-based catalysts for visible-light-driven photocatalysis.

Photocatalytic CO2 reduction on metal-oxide-based catalysts is promising for solving the energy and environmental crises faced by mankind. The oxygen vacancy (Vo) on metal oxides is expected to be a key factor affecting the efficiency of photocatalytic CO2 reduction on metal-oxide-based catalysts. Yet, to date, the question of how an Vo influences photocatalytic CO2 reduction is still unanswered. Herein, we report that, on Vo-rich gallium oxide coated with Pt nanoparticles (Vo-rich Pt/Ga2O3), CO2 is photocatalytically reduced to CO, with a highly enhanced CO evolution rate (21.0 μmol·h−1) compared to those on Vo-poor Pt/Ga2O3 (3.9 μmol·h−1) and Pt/TiO2(P25) (6.7 μmol·h−1). We demonstrate that the Vo leads to improved CO2 adsorption and separation of the photoinduced charges on Pt/Ga2O3, thus enhancing the photocatalytic activity of Pt/Ga2O3. Rational fabrication of an Vo is thereby an attractive strategy for developing efficient catalysts for photocatalytic CO2 reduction.

Inspired by natural photosynthesis, biomaterial-based catalysts are being confirmed to be excellent for visible-light-driven photocatalysis, but are far less well explored. Herein, an ultrathin and uniform biofilm fabricated from cold-plasma-assisted peptide self-assembly was employed to support Eosin Y (EY) and Pt nanoparticles to form an EY/Pt/Film catalyst for photocatalytic water splitting to H2 and photocatalytic CO2 reduction with water to CO, under irradiation of visible light. The H2 evolution rate on EY/Pt/Film is 62.1 μmol h–1, which is about 5 times higher than that on Pt/EY and 1.5 times higher than that on the EY/Pt/TiO2 catalyst. EY/Pt/Film exhibits an enhanced CO evolution rate (19.4 μmol h–1), as compared with Pt/EY (2.8 μmol h–1) and EY/Pt/TiO2 (6.1 μmol h–1). The outstanding activity of EY/Pt/Film results from the unique flexibility of the biofilm for an efficient transfer of the photoinduced electrons. The present work is helpful for designing efficient biomaterial-based catalysts for visible-light-driven photocatalysis and for imitating natural photosynthesis.Keywords: CO2 reduction; electron transfer flexibility; peptide self-assembled biofilm; visible-light-driven photocatalysis; water splitting;