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Non-noble metal for surface plasmon resonance (SPR)-induced nano-enzymatic photoelectrochemical (PEC) biosensors is a promising method for broad applications. Non-noble metal bismuth (Bi) is gradually being valued for their properties such as non-toxicity, abundant reserves, and good catalysis. Meanwhile, metallic Bi nanoparticles (NPs) have superior SPR properties similar to that of noble metal. Therefore, a non-noble metal Bi/BiVO4 photoanode based on SPR was designed for the PEC detection of H2O2 in this work. The synergistic effect of BiVO4 with suitable band gap (2.5 eV) and Bi NPs with superior SPR effectively reduces the recombination of photogenerated electrons and holes, which significantly improves the PEC activity of Bi/BiVO4 electrode at low voltage. The in situ Bi/BiVO4/FTO photoelectrode not only exhibits a more comprehensive linear range of 0.005–2.6 mM with a lower detection limit of 2.0 μM but also possesses excellent selectivity for the determination of H2O2 because the coexisting substances are difficult to be oxidized at 0 V bias voltage. The investigation of Bi/BiVO4-based sensor has contributed to the development of non-noble metal for SPR-induced PEC biosensors. [ABSTRACT FROM AUTHOR]

In this work, the typical honeycomb-nanoparticle heterostructure with honeycomb TiO 2 nanotube arrays (HTNTs) as light harvesting unit and Bi 2 MoO 6 nanoparticles (BMO) as recognition unit was prepared for highly sensitive and selective nano-enzymatic photoelectrochemical L-cysteine biosensor. [Display omitted] • The typical honeycomb-nanoparticle heterostructure between HTNTs and BMO improves the light harvesting behavior and the separation efficiency of the electron-hole pairs. • BMO nanoparticles fully dispersed on HTNTs with large specific surface area provides more sites for Cyst recognition. • Cyst can be specifically recognized through the Bi-S bonds. • The PEC enzyme-free biosensor shows good performance for Cyst with low detection limit and wide linear range. Improving light harvesting behavior and recognition sites of sensor is an effective way to achieve highly sensitive and selective detection of nano-enzymatic photoelectrochemical (PEC) L-cysteine (Cyst). In this work, the Bi 2 MoO 6 -TiO 2 composite (BMO-HTNTs) with honeycomb TiO 2 nanotube arrays (HTNTs) as light harvesting unit and Bi 2 MoO 6 nanoparticles (BMO) as recognition unit was prepared. The typical honeycomb-nanoparticle heterostructure between HTNTs and BMO improves the separation efficiency of the electron-hole pairs. Moreover, BMO nanoparticles fully dispersed on HTNTs with large specific surface area provide more sites for Cyst recognition. The composite exhibited the enhanced light absorption and higher photocurrent density at 0.2 V (vs. Ag/AgCl), which was 4 times than that of HTNTs under simulated light. Ingeniously, Cyst can not only be specifically recognized through the Bi-S bonds but also act as electron donor to scavenge the photogenerated holes of BMO-HTNTs, resulting in the increase of PEC responses. The PEC sensor showed superior analytical performance for Cyst detection with two linear regression equations in the range of 500 nM to 500 μM and a detection limit of 150 nM. The results of the enzyme-free sensor on practical urine and serum samples demonstrated its promising application in biological monitoring. [ABSTRACT FROM AUTHOR]