: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are three key reactions for the development of green and sustainable energy systems. Efficient electrocatalysts for these reactions are highly desired to lower their overpotentials and promote practical applications of related energy devices. Metal–organic frameworks (MOFs) have recently emerged as precursors to fabricate carbon-based electrocatalysts with high electrical conductivity and uniformly distributed active sites. In this review, the current progress of MOF-derived carbon-based materials for ORR/OER/HER electrocatalysis is presented. Materials design strategies of MOF-derived carbon-based materials are firstly summarized to show the rich possibilities of the morphology and composition of MOF-derived carbon-based materials. A wide range of applications based on these materials for ORR, OER, HER and multifunctional electrocatalysis are discussed, with an emphasis on the required features of MOF-derived carbon-based materials for the electrocatalysis of corresponding reactions. Finally, perspectives on the development of MOF-derived carbon-based materials for ORR, OER and HER electrocatalysis are provided.

MOF-derived electrocatalysts for oxygen reduction, oxygen evolution and hydrogen evolution reactions

Integration of advanced nanogenerator technology with conventional textile processes fosters the emergence of textile-based nanogenerators (NGs), which will inevitably promote the rapid development and widespread applications of next-generation wearable electronics and multifaceted artificial intelligence systems. NGs endow smart textiles with mechanical energy harvesting and multifunctional self-powered sensing capabilities, while textiles provide a versatile flexible design carrier and extensive wearable application platform for their development. However, due to the lack of an effective interactive platform and communication channel between researchers specializing in NGs and those good at textiles, it is rather difficult to achieve fiber/fabric-based NGs with both excellent electrical output properties and outstanding textile-related performances. To this end, a critical review is presented on the current state of the arts of wearable fiber/fabric-based piezoelectric nanogenerators and triboelectric nanogenerators with respect to basic classifications, material selections, fabrication techniques, structural designs, and working principles, as well as potential applications. Furthermore, the potential difficulties and tough challenges that can impede their large-scale commercial applications are summarized and discussed. It is hoped that this review will not only deepen the ties between smart textiles and wearable NGs, but also push forward further research and applications of future wearable fiber/fabric-based NGs.

Fiber/Fabric-Based Piezoelectric and Triboelectric Nanogenerators for Flexible/Stretchable and Wearable Electronics and Artificial Intelligence.

Designing atomically dispersed metal catalysts for oxygen reduction reaction (ORR) is a promising approach to achieve efficient energy conversion. Herein, we develop a template-assisted method to synthesize a series of single metal atoms anchored on porous N,S-codoped carbon (NSC) matrix as highly efficient ORR catalysts to investigate the correlation between the structure and their catalytic performance. The structure analysis indicates that an identical synthesis method results in distinguished structural differences between Fe-centered single-atom catalyst (Fe-SAs/NSC) and Co-centered/Ni-centered single-atom catalysts (Co-SAs/NSC and Ni-SAs/NSC) because of the different trends of each metal ion in forming a complex with the N,S-containing precursor during the initial synthesis process. The Fe-SAs/NSC mainly consists of a well-dispersed FeN4S2 center site where S atoms form bonds with the N atoms. The S atoms in Co-SAs/NSC and Ni-SAs/NSC, on the other hand, form metal-S bonds, resulting in CoN3S1 and NiN3S1 center sites. Density functional theory (DFT) reveals that the FeN4S2 center site is more active than the CoN3S1 and NiN3S1 sites, due to the higher charge density, lower energy barriers of the intermediates, and products involved. The experimental results indicate that all three single-atom catalysts could contribute high ORR electrochemical performances, while Fe-SAs/NSC exhibits the highest of all, which is even better than commercial Pt/C. Furthermore, Fe-SAs/NSC also displays high methanol tolerance as compared to commercial Pt/C and high stability up to 5000 cycles. This work provides insights into the rational design of the definitive structure of single-atom catalysts with tunable electrocatalytic activities for efficient energy conversion.

Tuning the Coordination Environment in Single-Atom Catalysts to Achieve Highly Efficient Oxygen Reduction Reactions.

Heteroatom-doped Fe-NC catalyst has emerged as one of the most promising candidates to replace noble metal-based catalysts for highly efficient oxygen reduction reaction (ORR). However, delicate controls over their structure parameters to optimize the catalytic efficiency and molecular-level understandings of the catalytic mechanism are still challenging. Herein, a novel pyrrole-thiophene copolymer pyrolysis strategy to synthesize Fe-isolated single atoms on sulfur and nitrogen-codoped carbon (Fe-ISA/SNC) with controllable S, N doping is rationally designed. The catalytic efficiency of Fe-ISA/SNC shows a volcano-type curve with the increase of sulfur doping. The optimized Fe-ISA/SNC exhibits a half-wave potential of 0.896 V (vs reversible hydrogen electrode (RHE)), which is more positive than those of Fe-isolated single atoms on nitrogen codoped carbon (Fe-ISA/NC, 0.839 V), commercial Pt/C (0.841 V), and most reported nonprecious metal catalysts. Fe-ISA/SNC is methanol tolerable and shows negligible activity decay in alkaline condition during 15 000 voltage cycles. X-ray absorption fine structure analysis and density functional theory calculations reveal that the incorporated sulfur engineers the charges on N atoms surrounding the Fe reactive center. The enriched charge facilitates the rate-limiting reductive release of OH* and therefore improved the overall ORR efficiency.

Fe Isolated Single Atoms on S, N Codoped Carbon by Copolymer Pyrolysis Strategy for Highly Efficient Oxygen Reduction Reaction

Applications of conducting polymer composites to electrochemical sensors: A review

Dithiooxamide (DTO), an organic ligand, is used to synthesize a ZnDTO framework, which acts as a precursor for self-doping of heteroatoms in the presence of hemoglobin via carbonization process for S and N doped carbon (SNC) and Fe-SNC. The sphere shaped porous carbon particles having a graphene network exhibit excellent performance for energy conversion and energy storage applications.

Template Free Preparation of Heteroatoms Doped Carbon Spheres with Trace Fe for Efficient Oxygen Reduction Reaction and Supercapacitor

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 wileyonlinelibrary.com catalysts for the oxygen reduction reaction (ORR) in alkaline conditions,[5] electrodes consisting of AuPd, AuPt, PtNi, and PdAg alloys have been studied because of their excellent activities compared to pure noble metals.[6–9] Based on these previous studies, the d-orbital coupling effect between metal atoms that have a low occupancy of the d-orbitals (Co, Ni, Cr, or V) and atoms with fully occupied d–orbitals (Pd, Au, and Ag) can significantly enhance the catalytic kinetics of the ORR, the oxygen evolution reaction (OER), and the hydrogen evolution reaction (HER).[10,11] Among these studies on metal alloys, Nicontaining catalysts in particular have received significant attention due to their excellent catalytic activity, low cost, and stability;[12] however, Ni shows a high cytotoxicity. Therefore, removing the Ni contents from the active material without affecting its use in biological applications is a necessary step. Studies on the morphology of metal nanostructures have provided opportunities to improve their shape-dependent catalytic activity, stability, and performance for electrocatalysis and electroanalysis.[13,14] Their chemical and physical properties can be tuned by controlling their shape, size, and crystallinity.[2,15] Dendritic structured catalysts are an important class of materials due to their high surface area, porosity, high degree of conductivity, and catalytic properties. Generally, nanoparticles or nanostructured materials are prepared by reducing metal salts, using a reducing agent, in the presence of surfactants to control their shape, size, and composition.[16] However, chemical techniques are time consuming, and the reducing agents are generally toxic. In contrast, electrochemical methods have recently received much attention because of the benefits of being simple, ecofriendly, and easy to operate.[17] Nanoparticles or dendrites are promising materials to achieve high efficiencies, but their limited stability, due to the corrosion of carbon, the dissolution of metal ions, Ostwald ripening, and the aggregation of nanoparticles,[18] presents a shortcoming that inhibits the large-scale commercialization of nanoparticles. To overcome these disadvantages, we examined a conducting polymer bearing functional groups that can stably capture catalytic metals. In the last decade, conducting Dealloyed AuNi Dendrite Anchored on a Functionalized Conducting Polymer for Improved Catalytic Oxygen Reduction and Hydrogen Peroxide Sensing in Living Cells

Dealloyed AuNi Dendrite Anchored on a Functionalized Conducting Polymer for Improved Catalytic Oxygen Reduction and Hydrogen Peroxide Sensing in Living Cells

Sensitive and selective detection of nitric oxide (NO) in the human body is crucial since it has the vital roles in the physiological and pathological processes. This study reports a new type of electrochemical NO biosensor based on zinc-dithiooxamide framework derived porous ZnO nanoparticles and polyterthiophene-rGO composite. By taking advantage of the synergetic effect between ZnO and poly(TTBA-rGO) (TTBA = 3'-(p-benzoic acid)-2,2':5',2″-terthiophene, rGO = reduced graphene oxide) nanocomposite layer, the poly(TTBA-rGO)/ZnO sensor probe displays excellent electrocatalytic activity and explores to detect NO released from normal and cancer cell lines. The ZnO is immobilized on a composite layer of poly(TTBA-rGO). The highly porous ZnO offers a high electrolyte accessible surface area and high ion-electron transport rates that efficiently catalyze the NO reduction reaction. Amperometry with the modified electrode displays highly sensitive response and wide dynamic range of 0.019-76 × 10-6 m with the detection limit of 7.7 ± 0.43 × 10-9 m. The sensor probe is demonstrated to detect NO released from living cells by drug stimulation. The proposed sensor provides a powerful platform for the low detection limit that is feasible for real-time analysis of NO in a biological system.

Malenahalli H. Naveen

Papers

Applications of conducting polymer composites to electrochemical sensors: A review

Template Free Preparation of Heteroatoms Doped Carbon Spheres with Trace Fe for Efficient Oxygen Reduction Reaction and Supercapacitor

Dealloyed AuNi Dendrite Anchored on a Functionalized Conducting Polymer for Improved Catalytic Oxygen Reduction and Hydrogen Peroxide Sensing in Living Cells

Detection of Nitric Oxide from Living Cells Using Polymeric Zinc Organic Framework-Derived Zinc Oxide Composite with Conducting Polymer.

Gold Nanoclusters as Electrocatalysts: Atomic Level Understanding from Fundamentals to Applications