共价键调控电荷转移以实现自供能电化学传感平台对重金属离子的灵敏分析OA

Rational design of photoelectric active materials for photoanodes in photocatalytic fuel cells is crucial for developing highly sensitive self-powered electrochemical sensors.Achieving directional migration and shortening transmission pathways of charge in photoanodes remains a fundamental challenge for enhancing the oxygen evolution reaction performance of photocatalytic fuel cells.Herein,tungsten species atomically dispersed on carbon-rich graphitic carbon nitride(W-CN-C)with the N-W-O covalent bond was designed as the photoanode for constructing a self-powered photocatalytic fuel cell sensing of heavy metal copper ions.W-CN-C was synthesized by self-assembly,exfoliation,and thermal-induced treatment process.The N-W-O covalent bonds by anchoring tungsten atoms on carbon-rich carbon nitride served as an interfacial charge transport channel,facilitating the separation and migration of charge carriers.The carbon content increase by forming a carbon-rich structure can enhance π-electron delocalization in the W-CN-C,significantly broadening sunlight utilization range.The dispersed tungsten atoms provide effectively active sites,promoting the kinetics of the oxygen evolution reaction between the W-CN-C photoanode and electrolyte interface.The synergistic effects significantly enhance the visible light absorption ability and charge separation and transfer efficiency,improving the photoelectric conversion efficiency of W-CN-C photoanode,exhibiting superior oxygen evolution reaction performance,leading to the amplified open circuit potential in the photocatalytic fuel cell system based on excellent oxygen reduction reaction performance of the Pt@C electrocatalyst cathode.The specific identification probe for copper ions was effectively anchored on the W-CN-C photoanode to construct a self-powered photocatalytic fuel cell sensing platform for copper ions detection.The complex formed by copper ions and the probe hindered electron transport at the W-CN-C photoanode,altering the output detection signal of the photocatalytic fuel cell,thus demonstrating a broad detection range spanning five orders of magnitude(2.0×10-2-9.2×102 nmol L-1),a low limit of detection(7.0 pmol L-1),high selectivity against common interferents,and applicability for detecting heavy metal copper ions in the aquatic environment.Furthermore,the platform allowed for self-powered and portable determination of copper ions using a multimeter as a signal output device,achieving a detection range of 0.25-1.3×102 nmol L-1 and a limit of 84 pmol L-1.This work proposes an approach for developing a high-performance photoanode utilizing atomically dispersed metals to introduce covalent bonds as charge transfer channels,paving the way for highly sensitive self-powered electrochemical sensors for environmental monitoring.