PdCu alloy nanosheets-constructed 3D flowers: New highly sensitive materials for H2S detection

•A new electrochemical sensor is developed for the detection of H2S.•PdCu alloy NFs exhibits high selectivity and sensitivity for the detection of H2S.•Sensing events can be accomplished under physiological conditions (pH7.4).•The mechanism is an electrochemical reaction of H2S with copper and its oxides. Hydrogen sulfide (H2S) could be directly produced in mammals and recognized as a third gasotransmitter, which are closely associated with physiological and pathological processes. However, the detailed mechanism remains unclear, mainly due to a lack of robust sensors to accurately and quantitatively detect its concentrations in biological samples. Herein, for the first time, we develop a new electrochemical sensor for the detection of H2S based on the chemical reaction between copper oxide (CuO and Cu2O) and hydrogen sulfide (including H2S and HS−) at a neutral solution (pH 7.4). Interestingly, when Na2S exists, copper and its oxide can be converted into Cu2S and CuS, resulting in an increase in the oxidation peak current of Cu2S-CuS with the increase of Na2S concentration, which is a direct evidence confirming the excellent sensor for the H2S detection. More importantly, the linear relationship between the oxidation peak currents of Cu2S-CuS and Na2S concentration is observed from 0.4 μM to 400 μM with a low detection limit of 0.2 μM, and satisfying selectivity. The developed strategy may have a great potential for further understanding the roles that biological H2S plays in biological systems.