| Chlorophenols(CPs)is a kind of persistent organic pollutants,which is characterized by toxicity,carcinogenicity and bioaccumulation.CPs usually is used as pesticide,herbicide and antibacterial Agent.CPs which have been utilized in our production and life migrate into water to lead to extremely water pollution which hurt the human health and safe of ecology and environment.So,it is necessary to developed a high efficiency and environment-friendly technology of degrading CPs.The electrocatalytic hydrodechlorination(EHDC)technology is relatively new for effective degrading CPs.Compared with traditional technology of degrading CPs,The EHDC technology possess characteristic of highly active,low second risk and easy operation,which is a promising technolygy.The metal Palladium(Pd)is common catalyst for EHDC technology.According to the problem about effenciency and energy of EHDC reaction on Pd nanomaterials,this paper mainly studies identifying the rate-determining step and optimizing the efficiency and energy consumption of EHDC on Pd nanomaterials.Firstly,Identify the desorption of phenol(P)is rate-determining step of the EHDC on Pd nanomaterials through comparing the EHDC performance of TiN-Pd and C-Pd.This paper takes 2,4-dichlorophenol(2,4-DCP)as typical CPs pollutants.We investigate that the difference between TiN-Pd and C-Pd in the EHDC efficiency,the yiled of H* and the adsorption behavior of 2,4-DCP and P by experiments and DFT calculations.Therefore,we found that P takes competitive adsorption with 2,4-DCP to occupy the sites of adsorption to poison it and then know that the desorption of 2,4-DCP is rate-determining step.we believe that it is possible that the d band centre could be descriptor for the EHDC.Compared with C supporting,TiN supporting decreases the d band centre of Pd and weakens the adsorption strength between Pd and P,and then P becomes easy to desorb from Pd to alleviate the poisonous effect of P.Herein,the d band centre owns potential ability to be descriptor for the EHDC efficiency.Furthermore,we could employ the d band centre to systematically thinking of the balance of adsorption of 2,4-DCP and desorption of P,which is a great strategy for enhancing the EHDC.However,the EHDC current efficiency on TiN-Pd is a little lower than C-Pd,which indicates that although the TiN-Pd reduces the poison of P for enhancing the EHDC efficiency,it also little decreases the energy consumption.In view of problem of energy consumption in the EHDC,we explore the synergistic catalytic effect of supporting to enhance that the adsorption of pollutions on Pd nanoparticles(Pd NPs)for improving the EHDC efficiency and lowing the consumption of energy.Developing the method for preparation of MgAlLDH-Pd electrocatalysis.We have studied the different PH effects the EHDC of MgAlLDH-Pd and C-Pd,and then we have identified that the MgAlLDH utilizes the electrostatic interaction and complexation to synergistic adsorb 2,4-DCP,which enhances effective adsorption of 2,4-DCP on Pd NPs to improve the EHDC efficiency and lowing the consumption of energy.Additionally,we have studied the varied potentials effect the EHDC of MgAlLDH-Pd and C-Pd,and then sure that MgAlLDH employs its character of positive charge to weak the repulsive interaction between the cathode and ionized 2,4-DCP,increasing the mass transfer of 2,4-DCP,enhancing effective adsorption of 2,4-DCP on Pd NPs,and improving the EHDC efficiency and lowing the consumption of energy.Then,Compared MgAlLDH-Pd with C-Pd in the HER(parasitic reaction),MgAlLDH-Pd reduces HER for contributing to increase the EHDC currency effeciency.Herein,the synergistic catalytic effect of supporting results in enhancing the EHDC efficiency.This paper studies that identifying the rate-determing step and optimizing the effenciency and energy of of EHDC reaction on Pd nanomaterials,which helps develop the catalyst of EHDC of high efficiency and low energy consumption for achieving the great performance in remediation of waste water. |
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