A homopolyacid-vanadate

namely dodecavanadic acid(H

2

V

12

O

31

)is prepared by sol-gel method and deposited onto the surface of bismuth oxyiodide/fluorine-doped tin oxide(BiOI/FTO) electrodes using the cyclic voltammetry method

with the expectation of combining the excellent properties

of the polyacid(high electrocatalytic activity

continuous and reversible multi-electron transfer ability

and strong redox ability)for the matching between the polyacid energy level structure and the BiOI energy levels

in order to improve the performance of the BiOI/FTO electrodes and to enhance the photoelectric catalytic activity of the composite electrode.The detection of tetracycline hydrochloride is studied using H

2

V

12

O

31

/BiOI/FTO as the working electrode

and the intensity of the photoelectric response decreases with the increase of the concentration of tetracycline hydrochloride within the range of 0.1~1000μmol/L

which shows a good linear relationship

and the linear equation is

I

(μA cm

-2

)=2.843log

C

TC

(μmol/L)-10.417μA

the sensitivity is 113.153μA(mmol/L)

-1

cm

-2

and the limit of detection(LOD)(

S

/

N

=3)is 0.470μmol/L.The experimental results show that the sensor has a wide detection range for tetracycline and has good selectivity and stability.