High-temperature solar steam generation by MWCNT-HfTe2 van der Waals heterostructure for low-cost sterilization

Abstract

Conventional steam sterilization for medical equipment requires electricity and significant initial capital cost, impeding its uses in many resource-constrained areas and exposing patients to nosocomial infections. The urgent need for a low-cost and environmentally friendly approach for the sterilization process can be addressed by utilizing abundant solar irradiance and an efficient solar absorber. Herein, for the first time, 1D–2D metallic MWCNTs and HfTe2 van der Waals heterostructure are used for realizing broadband solar absorption with an evaporation efficiency of 87.43% under one sun illumination resulting in an increase in steam temperature to 132 °C in < 20 mins. The facile fabrication process and minimalist design substantially reduced sterilization cost to only ¢0.21 per liter capacity. Furthermore, a proof-of-concept sterilizing demonstration resulted in a 99.04% reduction in E. coli bacteria, exceeding the requirements of the World Health Organization. Such a sterilization system would reduce 2.45 tons of CO2 emissions annually by substituting a 10 L capacity conventional autoclave. Hence, the MWCNT-HfTe2@Cu foam-based medical sterilizing system could be a promising and low-cost sterilization solution in off-grid and resource constrained areas due to its superb sterilizing performance, dramatic capital and operating cost reduction capability, ease of maintenance, and a significant reduction in carbon footprint.