Facile synthesis of Nafion-supported Pt nanoparticles with ultra-low loading as a high-performance electrocatalyst for hydrogen evolution reaction

Yu, Jianguo,Wei, Dan,Zheng, Zhe,Yu, Wenjie,Shen, Honghui,Qu, Yuning,Wen, Shuya,Kwon, Young-Uk,Zhao, Yongnan Elsevier 2020 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.566 No.-

<P><B>Abstract</B></P> <P>x%Pt-Naf-CV (Pt-Nafion-Cyclic Voltammetry) catalysts with homogeneously distributed platinum nanoparticles and ultra-low Pt loading are successfully synthesized by using a facile potential cycling approach. The as-synthesized 0.8%Pt-Naf-CV catalyst exhibits an enhanced electrocatalytic activity for hydrogen evolution reaction (HER) in 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB> solution, which obtains a low overpotential of 34 mV at 10 mA cm<SUP>−2</SUP>. The linear sweep voltammetry (LSV) curve of 0.8%Pt-Naf-CV catalyst is almost consistent with that of commercial Pt/C. However, the 0.8%Pt-Naf-CV catalyst displays a more excellent stability and durability in comparison with commercial Pt/C. Besides, the Pt loading of Pt/C (Pt–10 wt%) is about 10 times that of 0.8%Pt-Naf-CV catalyst. The improved electrocatalytic performances are derived from the synergistic effects of Pt and Nafion. The Nafion plays a significant role as a dispersant, carrier and structure directing agent on the morphology and size of the Pt catalyst. This result contributes a promising method to enhance the catalytic activity and reduce the amount of Pt.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Sand cat arithmetic optimization algorithm for global optimization engineering design problems

Chen Shuilin,Zheng Jianguo 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

Sand cat swarm optimization (SCSO) is a recently introduced popular swarm intelligence metaheuristic algorithm, which has two significant limitations – low convergence accuracy and the tendency to get stuck in local optima. To alleviate these issues, this paper proposes an improved SCSO based on the arithmetic optimization algorithm (AOA), the refracted opposition-based learning and crisscross strategy, called the sand cat arithmetic optimization algorithm (SC-AOA), which introduced AOA to balance the exploration and exploitation and reduce the possibility of falling into the local optimum, used crisscross strategy to enhance convergence accuracy. The effectiveness of SC-AOA is benchmarked on 10 benchmark functions, CEC 2014, CEC 2017, CEC 2022, and eight engineering problems. The results show that the SC-AOA has a competitive performance.

Thermal Conductivity of Loess: Experimental Studies and Empirical Model

Jingjing Wang,Juntao Deng,Jianguo Zheng,Tiehang Wang,Yongtang Yu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

Soil thermal conductivity is an important indicator for developing and utilizing geothermal resources. In this study, the impact of underground environmental factors on the thermal conductivity of loess was explored by studying the thermal conductivity of saturated and unsaturated loess under varying water content, dry density, and temperature using the Hot Disk thermal constant analyzer. The results show that the thermal conductivity of unsaturated undisturbed and remolded loess presents different growth trends as the water content increases. When the water content is less than 9%, the thermal conductivity of undisturbed soil increases slowly. The thermal conductivity of unsaturated loess gradually increases with temperature. When the temperature rises above 30oC, the latent heat transfer of steam gradually strengthens, accelerating the increase in thermal conductivity, which is most noticeable at intermediate saturation. However, the thermal conductivity of saturated loess rises slowly as the temperature rises. A weighted geometric average model is proposed in this study to predict the thermal conductivity of loess under temperature conditions, considering the effects of soil water content, dry density, and mineral content. The model accuracy was corroborated by the measured soil thermal conductivity and the data collected from six regions.

Vagococcus zengguangii sp. nov., isolated from yak faeces

Ge Yajun,Jin Dong,Lai Xin-He,Yang Jing,Lu Shan,Huang Ying,Zheng Han,Zhang Xiaoyan,Xu Jianguo 한국미생물학회 2021 The journal of microbiology Vol.59 No.1

Two unknown Gram-stain-positive, catalase- and oxidasenegative, non-motile, and coccus-shaped bacteria, designated MN-17T and MN-09, were isolated from yaks faeces (Bos grunniens) in the Qinghai-Tibet Plateau of China. 16S rRNA gene sequence-based comparative analyses revealed that the two strains were grouped within the genus Vagococcus, displaying the highest similarity with Vagococcus xieshaowenii CGMCC 1.16436T (98.6%) and Vagococcus elongatus CCUG 51432T (96.4%). Both strains grew optimally at 37°C and pH 7.0 in the presence of 0.5% (w/v) NaCl. The complete genome of MN-17T comprises 2,085 putative genes with a total of 2,190,262 bp and an average G + C content of 36.7 mol%. The major fatty acids were C16:0 (31.2%), C14:0 (28.5%), and C18:1ω9c (13.0%); the predominant respiratory quinone was MK-7 (68.8%); the peptidoglycan type was A4α(L-Lys-DAsp); and the major polar lipid was diphosphatidylglycerol. Together, these supported the affiliation of strain MN-17T to the genus Vagococcus. In silico DNA-DNA hybridization and the average nucleotide identity values between MN-17T and all recognized species in the genus were 21.6–26.1% and 70.7–83.0%, respectively. MN-17T produced acid from D-cellobiose, D-fructose, glycerol, D-glucose, N-acetyl-glucosamine, gentiobiose, D-mannose, D-maltose, D-ribose, Dsaccharose, salicin, D-trehalose, and D-xylose. These results distinguished MN-17T and MN-09 from closely related species in Vagococcus. Thus, we propose that strains MN-17T and MN-09 represent a novel species in the genus Vagococcus, with the name Vagococcus zengguangii sp. The type strain is MN-17T (= CGMCC 1.16726T = GDMCC 1.1589T = JCM 33478T).

Agromyces laixinhei sp. nov. isolated from bat feces in China

Cheng Yanpeng,Bai Yibo,Huang Yuyuan,Yang Jing,Lu Shan,Jin Dong,Pu Ji,Zheng Han,Li Junqin,Huang Ying,Wang Suping,Xu Jianguo 한국미생물학회 2021 The journal of microbiology Vol.59 No.5

Three rod-shaped, Gram-stain-positive, and catalase-positive, phenotypically closely related isolates (HY052T, HY050, and HY045) were obtained from fecal samples collected from bats in Guangxi province and Chongqing city of China. Circular, smooth, light-yellow colonies appeared on brain heart infusion plate after 24–48 h incubation at 28°C. The optimal pH for growth was between 6.0 and 7.5. Based on 16S rRNA, the three isolates were phylogenetically related to Agromyces terreus DS-10T, Agromyces aureus AR33T, Agromyces salentinus 20-5T, Agromyces allii UMS-62T, Agromyces lapidis CD55T, and Agromyces italicus CD1T. Moreover, based on 296 core genes, the phylogenomic tree indicated that the three isolates clustered together, closest to Agromyces cerinus VKM Ac- 1340T and Agromyces fucosus VKM Ac-1345T but separated distantly from other Agromyces species. The average nucleotide identity values between strain HY052T and other Agromyces species ranged from 79.3% to 87.9%, lower than the 95–96% threshold. Furthermore, the genome of strain HY052T contains a circular chromosome of 3,437,203 bp with G + C content of 69.0 mol%. Main fatty acids were anteiso-C15:0 and anteiso-C17:0. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, and unidentified glycolipids. Rhamnose, ribose, and glucose were the primary cell wall sugars. The major peptidoglycan amino acids included alanine, glutamic acid, glycine, and 2,4-diaminobutyric acid. An additional remarkable difference from other Agromyces species is that MK-12 was the sole menaquinone in strain HY052T. Based on results from the polyphasic characterizations performed in this study, our isolates are proposed to be members of a novel species in genus Agromyces, named Agromyces laixinhei. The type strain is HY052T (= CGMCC 1.17175T = JCM 33695T).