Highly efficient visible-light-driven Cu2O@CdSe micromotors adsorbent

Micro/nanomotors have attracted extensive attentions in aquatic environmental remediation, but the random motion and uncontrollability restricts the precise location and timely adjustment in micro environmental remediation, such as in microchannels and microwells. Herein, we demonstrated visible light-driven cadmium sulfide quantum dots doped cuprous oxide (Cu2O@CdSe) micromotors adsorbent with excellent removability to cationic dye, in along with effective motion regulation. The Cu2O@CdSe micromotors adsorbent with type II heterostructure was fabricated by simple in-situ deposition and exhibited outstanding motion controllability and instant response under visible light illumination. The existence of a staggered gap between Cu2O and CdSe formed a heterojunction, effectively inhibiting recombination of photogenerated electron-hole pairs and improving photocatalytic activity of Cu2O@CdSe micromotors. Negative phototactic self-propulsion with maximum speed to similar to 42.3 mu m/s was achieved in biological environments because of the formation of the asymmetric chemical concentration gradient around the motors. Additionally, by modulating the direction and on/off state of asymmetric light field, it is capable of steering motor moving with multiple controllable modes, such as horizontal, vertical, stop/go and patterned propulsion, which will facilitate the on-demand orientation once in the complex microchannel. Furthermore, the capability of Cu2O@CdSe micromotors adsorbent is confirmed with a rapid adsorption rate of 96% on methyl blue after 10 min. Additionally, the stability of micromotors is evaluated. Although with inevitable oxidation or photocorrosion for all Cu2O micromotor, the strong adsorption ability is promised with 5 times recycling in low concentration of dye solution. Such attractive micromachines with boosted motility and lower production cost hold a considerable promise for a complex environmental remediation. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Visible light-driven Cu2O@CdSe micromotors with excellent removal performance and effective motion regulation show promising applications in micro environmental remediation.