One-pot bottom-up fabrication of a 2D/2D heterojuncted nanozyme towards optimized peroxidase-like activity for sulfide ions sensing

The cutting-edge nanozyme-based strategy for rapid detection remains significantly limited by the lack of simple synthetic method with ideal catalytic activity. In this regard, 2D nanozymes has recently emerged as a group of promising nanozymes because of their unique enzyme mimicking properties. Herein, via one-pot bottom-up co-calcination, we report a robust strategy to promote the peroxidase-like activity of 2D nanozyme by rational fabricating a 2D/2D heterojuncted nanozyme: MoS2/g-C3N4 heterojuncted nanosheets (MoS2/g-C3N4 HNs). With merits of the acceleration of electron transfer and the synergistic effect of MoS2 and g-C3N4 as well as high affinity to the catalytic substrates, the 2D/2D MoS2/g-C3N4 heterojuncted nanozyme shows enhanced peroxidase-like activity over the pure g-C3N4 nanosheets and MoS2 nanosheets. As a proof-of-concept application, a colorimetric sensor based on this 2D/2D heterojuncted nanozyme was developed to detect sulfide ions (S2−), and the detection limit was found to be as low as 37 nM. Therefore, the current work not only demonstrates a powerful strategy to improve the activity of 2D nanozymes but also establish a facile approach for water-safety monitoring.