Constructing high-effective electrode sensing interfaces has been considered an effective method for electrochemical detection toward heavy metal ions (HMIs). However, most research has been devoted to enhancing the stripping currents of HMIs by simply improving the adsorptive capacity and conductivity of the electrode modified materials, while lacking theoretical guidelines in fabricating catalytic sensing interfaces. Besides, the understanding of detection mechanisms is quite unscientific from the perspective of catalysis. This perspective summarizes five general strategies in designing highly efficient sensing interfaces in the recent five years, including modulating crystal phases, orientations and planes, defect engineering, ionic valence state cycle engineering, adsorption in situ catalysis strategy, and construction of atomic level catalytic active sites. What’s more, the catalytic mechanisms for improving the signals of HMIs, such as boosting the electron transfer rates and conversion rates, lowering the energy barriers, etc., are introduced and emphasized. This study has a great significance in directionally controlling functionalized electrochemical sensors to achieve excellent sensitivity and selectivity in detecting environmental pollutants from the view of catalysis, and it also brings enlightenments and guidance to develop new electroanalytical methods.

The irreconcilable conflict between stability and excellent electrocatalytic activity of Au nanoclusters greatly limits their application. Extensive efforts are devoted to fabricating various substrates to immobilize Au nanoclusters while it is still challenging to maintain its electrocatalytic activities for long term tasks due to the highly reactive environments that the Au nanoclusters encounter in electrocatalytic reactions. Herein, an unexpected "redispersion effect" is discovered when Au 25 nanoclusters are loaded on the nanocomposites of black phosphorus and N-doped graphene (AuCs/BP-NG), forming the sandwich configuration with the enhanced stability. The size of Au nanoclusters reduce from 1.56 ± 0.5 to 1.04 ± 0.2 nm, leading to improved catalytic ability. Such redispersion effect yields a super-high electrocatalytic performance of the AuCs/BP-NG toward Cr(VI) sensing that the detection sensitivity achieved 0.414 µA ppb −1 , which is two orders of magnitude higher than the state-of-the-art value. Compared with BP-NG and Au nanoparticles (AuNPs) loaded on BP-NG (AuNPs/BP-NG), the lowest reaction barrier in the rate-determining steps of H 2 CrO 4 reduction is observed. The findings provide an opportunity to develop a superior electrocatalyst in the community of energy and environment-related electrocatalysis.