@article {44148, title = {Cerium-based metal-organic framework having inherent oxidase-like activity applicable for colorimetric sensing of biothiols and aerobic oxidation of thiols}, journal = {Crystengcomm}, volume = {19}, year = {2017}, month = {OCT}, pages = {5915-5925}, type = {Article}, abstract = {A cerium-basedmetal-organic framework (MOF; 1) with a UiO-66 (UiO: University of Oslo) framework topology was synthesized solvothermally by employing 3,4-dimethylthieno[2,3-b] thiophene-2,5-dicarboxylic acid as a ligand. The MOF was thoroughly characterized by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction, infrared spectroscopy, and thermogravimetric and N-2 sorption analyses. The activated material (1{\textquoteright}) retained its structural integrity in water, acetic acid and 1 M HCl solution. XPS investigation reveals the presence of both Ce(III) and Ce(IV) ions in 1. Owing to the presence of mixed-valence cerium ions, 1{\textquoteright} was able to oxidize the chromogenic peroxidase substrate 3,3{\textquoteright}, 5,5{\textquoteright}-tetramethylbenzidine (TMB) or 2,2{\textquoteright}azinobis.3- ethylbenzothizoline-6-sulfonic acid) (AzBTS) in the absence of an external oxidizing agent. Thus, it showed inherent oxidase-like catalytic properties. Inspired by the excellent oxidase-mimicking activity of 1{\textquoteright}, a protocol was developed for the rapid colorimetric sensing of biothiols in NaAc buffer (0.2 M, pH = 4). The sensing ability of 1{\textquoteright} towards cysteine was also demonstrated in human blood plasma. Furthermore, the redox-active cerium ions enabled 1{\textquoteright} to exhibit excellent heterogeneous catalytic performance in aerobic oxidation catalysis of thiol compounds. The material is reusable (both as a sensor and as a catalyst), lowcost and highly stable, which renders it a promising candidate for the monitoring of biothiols in immunoassays and medical diagnosis as well as for industrial oxidation catalysis.}, doi = {10.1039/c7ce01053b}, author = {Dalapati, Rana and Sakthivel, Balasubramanian and Ghosalya, Manoj K. and Dhakshinamoorthy, Amarajothi and Biswas, Shyam} } @article {46250, title = { Molybdenum carbide catalyst for the reduction of CO2 to CO: surface science aspects by NAPPES and catalysis studies }, journal = {Dalton Transactions}, volume = {48}, year = {2019}, month = {AUG}, pages = {12199-12209}, type = {Article}, abstract = {

Carbon dioxide is a greenhouse gas, and needs to be converted into one of the useful feedstocks, such as carbon monoxide and methanol. We demonstrate the reduction of CO2 with H-2 as a reducing agent, via a reverse water gas shift (RWGS) reaction, by using a potential and low cost Mo2C catalyst. Mo2C was evaluated for CO2 hydrogenation at ambient pressure as a function of temperature, and CO2 : H-2 ratio at a gas hourly space velocity (GHSV) of 20 000 h(-1). It is demonstrated that the Mo2C catalyst with 1 : 3 ratio of CO2 : H-2 is highly active (58\% CO2 conversion) and selective (62\%) towards CO at 723 K at ambient pressure. Both properties (basicity and redox properties) and high catalytic activity observed with Mo2C around 700 K correlate well and indicate a strong synergy among them towards CO2 activation. X-ray diffraction and Raman analysis show that the Mo2C catalyst remains in the beta-Mo2C form before and after the reaction. The mechanistic aspects of the RWGS reaction were determined by near-ambient pressure X-ray photoelectron spectroscopy (NAPXPS) with in situ generated Mo2C from carburization of Mo-metal foil. NAPXPS measurements were carried out at near ambient pressure (0.1 mbar) and various temperatures. Throughout the reaction, no significant changes in the Mo2+ oxidation state (of Mo2C) were observed indicating that the catalyst is highly stable; C and O 1s spectral results indicate the oxycarbide species as an active intermediate for RWGS. A good correlation is observed between catalytic activity from atmospheric pressure reactors and the electronic structure details derived from NAPXPS results, which establishes the structure-activity correlation.

}, doi = {10.1039/c9dt01774g}, author = {Reddy, Kasala Prabhakar and Dama, Srikanth and Mhamane, Nitin B. and Ghosalya, Manoj K. and Raja, Thirumalaiswamy and Satyanarayana, Chilukuri V. and Gopinath, Chinnakonda S.} }