Highly dispersed 1 nm Pt Pd bimetallic clusters for formic acid electrooxidation through a CO-free mechanism

Direct formic acid fuel cell(DFAFC) is an important research project in clean energy field.However,commercialization of DFAFC is still largely limited by the available catalysts with unsatisfied activity,durability and cost for formic acid electrooxidation(FAEO).Using Pt-and Pd-based nanoclusters as electrocatalysts is a particularly promising strategy to solve the above problem,but two attendant problems need to be solved firstly.(Ⅰ) The controllable synthesis of practicable and stable sub-2 nm clusters remains challenging.(Ⅱ) The catalyzing mechanism of sub-2 nm metal clusters for FAEO has not yet completely understood.Herein,different from traditional solution synthesis,by designing a novel supporting material containing electron-rich and electron-deficient functional groups,size-and dispersioncontrollable synthesis of ~1 nm PtPd nanoclusters is realized by an electrochemical process.The electrocatalytic properties and reaction mechanism of the PtPd nanoclusters for the FAEO were studied by different electrochemical techniques,in-situ fourier transform infrared(FTIR) spectra and density functional theory(DFT) calculations.The tiny PtPd nanoclusters have much higher catalytic activity and durability than commercial Pt/C,Pd/C and 3.5 nm PtPd nanoparticles.The present study shows that the metalreactant interaction plays a decisive role in determining the catalytic activity and cluster-support interaction plays a decisive role in enhancing the durability of electrocatalyst.The ratio and arrangement of Pt and Pd atoms on the surface of 1 nm PtPd cluster as well as the overall valence state,d-band center and specific surface area make them exhibit different catalytic performance and reaction mechanism from nanoparticle catalysts.In addition,in situ FTIR and DFT calculations showed that on the surface of PtPd clusters,the generation of CO_(2)through trans-COOH intermediate is the most optimal reaction pathway for the FAEO.

Mechanism of acupuncture regulating visceral sensation and mobility

Chinese ancient medical scientists have long focused on the internal and external contacts between acupoints on the surface of the body and the viscera.The Miraculous Pivot(it is one of the earliest medical classics in China)stated,“Twelve regular channels belong to the zang-fu organs internally,and connect to the extremities and joints externally.”Traditional Chinese medicine considers acupoints as defined areas where the Qi of viscera and meridians are transfused.These include the reaction points of visceral diseases on the body surface as well as the acupuncture trigger points that promote the flow of Qi and blood,and regulate visceral function.Chinese ancient medical scientists classified the specificity of the main acupoints in the body based on the meridian doctrine,which has been instructing clinical application for about 2000 years.Laws on the domino effect of acupoints have mainly focused on conclusions to clinical experiences.Indications of some acupoints exceed the practical paradigm since the excessive extension occurred during theory derivation.The current research direction on acupuncture focuses on three aspects:the effectiveness of acupuncture and moxibustion;the relevances and associations between meridians and viscera;and the physical and chemical properties and relevant physical basis of acupoints.The relevance between meridians and viscera is the central theory in the meridian doctrine,and acupoints are regarded as an important link in the relationship between meridians and viscera.Specific relationships between acupoints and target organs exist.Stimulating different acupoints on the body surface can help deal with different diseases,especially visceral diseases.In addition,acupoints have a dual function of reflecting and treating visceral diseases.There is no systemic research available on acupoint specificity,despite current knowledge and clinical experiences,which results in a weak foundation for acupuncture theory.This study focuses on the relevance and associations between meridians and viscera.A summary of the mechanisms of acupuncture regulating visceral sensation and mobility and the specific relationships between acupoints and their target organs are presented in this review.