ABSTRACT
Electrocatalytic nitrate reduction reaction (NO3-RR) is an important route for sustainable NH3 synthesis and environmental remediation. Metal-organic frameworks (MOFs) are one family of promising NO3-RR electrocatalysts, however, there is plenty of room to improve in their performance, calling for new design principles. Herein, a MOF-on-MOF heterostructured electrocatalyst with interfacial dual active sites and build-in electric field is fabricated for efficient NO3-RR to NH3 production. By growing Co-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) nanorods on Ni-BDC (BDC=1,4-benzenedicarboxylate) nanosheets, experimental and theoretical investigations demonstrate the formation of Ni-O-Co bonds at the interface of MOF-on-MOF heterostructure, leading to dual active sites tailed for NO3-RR. The Ni sites facilitate the adsorption and activation of NO3-, while the Co sites boost the H2O decomposition to supply active hydrogen (Hads) for N-containing intermediates hydrogenation on adjacent Ni sites, cooperatively reducing the energy barriers of NO3-RR process. Together with the accelerated electron transfer enabled by built-in electric field, remarkable NO3-RR performance is achieved with an NH3 yield rate of 11.46 mg h-1 cm-2 and a Faradaic efficiency of 98.4%, outperforming most reported MOF-based electrocatalysts. This work provides new insights into the design of high-performance NO3-RR electrocatalysts.
ABSTRACT
The Bacillus velezensis YYC strain was isolated from the tomato rhizosphere. In a previous experiment, it increased tomato growth and induced systemic resistance against Ralstonia solanacearum. However, information on its genomic content is lacking. The complete genome sequence of the bacterium was described in this study. The genome size was 3,973,236 bp and consisted of 4034 genes in total, with a mean G + C content of 46.52%. In addition, 86 tRNAs and 27 ribosomal RNAs were identified. Fourteen clusters of secondary metabolites were identified. The KEGG database analysis showed that 69 genes were related to quorum sensing, which were important for microbe-plant interaction. In addition, genes involved in promoting plant growth and triggering plant immunity were identified from the genome. Based on digital DNA-DNA hybridizations (dDDH), B. velezensis YYC was most closely related with B. velezensis FZB42. The complete genome data of B. velezensis YYC will provide a basis for explanation of its growth-promoting mechanism and biocontrol mechanism.
