Motorized Photomodulator:Making A Non-photoresponsive Supramolecular Gel Switchable by Light

Introducing photo-responsive molecules offers an attractive approach for remote and selective control and dynamic manipulation of material properties. However, it remains highly challenging how to use a minimal amount of photo-responsive units to optically modulate materials that are inherently inert to light irradiation. Here we show that the application of a light-driven rotary molecular motor as a "motorized photo-modulator" to endow a typical H-bond-based gel system with the ability to respond to light irradiation creating a reversible sol-gel transition. The key molecular design feature is the introduction of a minimal amount (1 mol%) of molecular motor into the supramolecular network as a photo-switchable non-covalent crosslinker. Advantage is taken of the subtle interplay of the large geometry change during photo-isomerization of the molecular motor guest and the dynamic nature of a supramolecular gel host system. As a result, a tiny amount of molecular motors is enough to switch the mechanical modulus of the entire supramolecular systems. This study proves the concept of designing photo-responsive materials with minimum use of non-covalent light-absorbing units.</p

carbonsupportedultrafineptnanoparticlesmodifiedwithtraceamountsofcobaltasenhancedoxygenreductionreactioncatalystsforprotonexchangemembranefuelcells

To accelerate the kinetics of the oxygen reduction reaction (orr) in proton exchange membrane fuel cells, ultrafine pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching. the obtained pt36co/c catalyst exhibits a much larger electrochemical surface area (ecsa) and an improved orr electrocatalytic activity compared to commercial pt/c. moreover, an electrode prepared with pt36co/c was further evaluated under h-2-air single cell test conditions, and exhibited a maximum specific power density of 10.27 w mg(pt)(-1),which is 1.61 times higher than that of a conventional pt/c electrode and also competitive with most state-of-the-art pt -based architectures. in addition, the changes in ecsa, power density, and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the pt36co/c electrode. the superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles, bimetallic ligand and electronic effects, and the dissolution of unstable co with the rearrangement of surface structure brought about by acid etching. furthermore, the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of pemfcs. (c) 2019, dalian institute of chemical physics, chinese academy of sciences. published by elsevier b.v. all rights reserved

carbonsupportedultrafineptnanoparticlesmodifiedwithtraceamountsofcobaltasenhancedoxygenreductionreactioncatalystsforprotonexchangemembranefuelcells

To accelerate the kinetics of the oxygen reduction reaction (orr) in proton exchange membrane fuel cells, ultrafine pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching. the obtained pt36co/c catalyst exhibits a much larger electrochemical surface area (ecsa) and an improved orr electrocatalytic activity compared to commercial pt/c. moreover, an electrode prepared with pt36co/c was further evaluated under h-2-air single cell test conditions, and exhibited a maximum specific power density of 10.27 w mg(pt)(-1),which is 1.61 times higher than that of a conventional pt/c electrode and also competitive with most state-of-the-art pt -based architectures. in addition, the changes in ecsa, power density, and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the pt36co/c electrode. the superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles, bimetallic ligand and electronic effects, and the dissolution of unstable co with the rearrangement of surface structure brought about by acid etching. furthermore, the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of pemfcs. (c) 2019, dalian institute of chemical physics, chinese academy of sciences. published by elsevier b.v. all rights reserved

Carbon-supported ultrafine Pt nanoparticles modified with trace amounts of cobalt as enhanced oxygen reduction reaction catalysts for proton exchange membrane fuel cells

To accelerate the kinetics of the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells, ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching. The obtained Pt36Co/C catalyst exhibits a much larger electrochemical surface area (ECSA) and an improved ORR electrocatalytic activity compared to commercial Pt/C. Moreover, an electrode prepared with Pt36Co/C was further evaluated under H-2-air single cell test conditions, and exhibited a maximum specific power density of 10.27 W mg(pt)(-1),which is 1.61 times higher than that of a conventional Pt/C electrode and also competitive with most state-of-the-art Pt -based architectures. In addition, the changes in ECSA, power density, and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the Pt36Co/C electrode. The superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles, bimetallic ligand and electronic effects, and the dissolution of unstable Co with the rearrangement of surface structure brought about by acid etching. Furthermore, the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of PEMFCs. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved