Study On The Preparation Of Porous Carbon Composite TiO₂ Cathode For Electrocatalytic Degradation Of Phenol From Discarded Tea Leaves

As a representative of phenols,phenol has a serious impact on human life and health.Electrochemical advanced oxidation technology（EAOP）has been widely used in the field of phenol degradation due to its energy saving and environmental protection of the process and easy operation.Biomass-derived porous carbon materials are considered to be a promising cathode material for electrocatalytic degradation of phenol due to their wide sources,low price,and unique structure.In this paper,tea-based porous carbon（TPC）was successfully prepared using waste tea as a biomass carbon source by means of activation,solid-phase liquid phase separation and carbonization.The preparation process is simple and template-free.The prepared TPC showed good physical and structural characteristics,including a large specific surface area(1620.05 m²g^-1),a three-dimensional hierarchical pore structure,a uniform pore size and a rich oxygen content.On this basis,titanium dioxide（TiO₂）prepared by the sol-gel method was combined with TPC in a hydrothermal manner to successfully acquire a TiO₂/TPC composite material.TiO₂ was uniformly coated on the TPC under the appropriate amount of sol,and a large number of catalytically active sites and abundant oxygen-containing groups were provided due to the presence of TiO₂ without destroying the structure of the material itself.These advantages can effectively guarantee the production of active substances such as oxygen free radicals and further decompose organic pollutants.The prepared TPC and TiO₂/TPC composite materials were selected as cathode materials,Ti/TrO₂/RuO₂ net was used as anode materials and Na₂SO₄ was used as an electrolyte solution to construct an electrocatalytic degradation system,an electrocatalytic degradation experiment was performed on phenol simulated wastewater,the electrocatalytic degradation mechanism was discussed on the basis.The experimental results show that for all the above experimental system,the most suitable degradation conditions are:current density 30 m A cm^-2,pH=3,initial phenol concentration 100 mg L^-1 and electrolyte concentration 0.10 mol L^-1.Under the above conditions,the degradation effect of TPC reached 95.41%after 120 min reaction,and the TiO₂/TPC composite material reached 97.54%.In addition,COD removal rates reached 90.00%and 90.21%in 180 min,respectively.On this basis,both TPC and TiO₂/TPC composite materials showed good stability.After repeated use for 20 times,the degradation effects can still reach 91.39% and 90.88%,respectively.