Highly efficient microbial inactivation enabled by tunneling charges injected through two-dimensional electronics.

Airborne pathogens retain prolonged infectious activity once attached to the indoor environment, posing a pervasive threat to public health. Conventional air filters suffer from ineffective inactivation of the physics-separated microorganisms, and the chemical-based antimicrobial materials face challenges of poor stability/efficiency and inefficient viral inactivation. We, therefore, developed a rapid, reliable antimicrobial method against the attached indoor bacteria/viruses using a large-scale tunneling charge-motivated disinfection device fabricated by directly dispersing monolayer graphene on insulators. Free charges can be stably immobilized under the monolayer graphene through the tunneling effect. The stored charges can motivate continuous electron loss of attached microorganisms for accelerated disinfection, overcoming the diffusion limitation of chemical disinfectants. Complete (>99.99%) and broad-spectrum disinfection was achieved <1 min of attachment to the scaled-up device (25 square centimeters), reliably for 72 hours at high temperature (60°C) and humidity (90%). This method can be readily applied to high-touch surfaces in indoor environments for pathogen control.

Self-Powered Water Splitting of Ni3FeN@Fe24N10 Bifunctional Catalyst Improved Catalytic Activity and Durability by Forming Fe24N10 on Catalyst Surface via the Kirkendall Effect.

Highly efficient water splitting electrocatalyst for producing hydrogen as a renewable energy source offers potential to achieve net-zero. However, it has significant challenges in using transition metal electrocatalysts as alternatives to noble metals due to their low efficiency and durability, furthermore, the reliance on electricity generation for electrocatalysts from fossil fuels leads to unavoidable carbon emissions. Here, a highly efficient self-powered water splitting system integrated is designed with triboelectric nanogenerator (TENG) and Ni3FeN@Fe24N10 catalyst with improved catalytic activity and durability. First, the durability of the Ni3FeN catalyst is improved by forming N, P carbon shell using melamine, polyetherimide, and phytic acid. The catalyst activity is improved by generating Fe24N10 in the carbon shell through the Kirkendall effect. The synthesized Ni3FeN@Fe24N10 catalyst exhibited excellent bifunctional catalytic activity (ηOER = 261.8 mV and ηHER = 151.8 mV) and remarkable stability (91.7% in OER and 90.5% in HER) in 1 m KOH. Furthermore, to achieve ecofriendly electricity generation, a rotation-mode TENG that sustainably generate high-performance is realized using butylated melamine formaldehyde. As a result, H2 is successfully generated using the integrated system composed of the designed TENG and catalyst. The finding provides a promising approach for energy generation to achieve net-zero.

Self-Powered Fine Dust Filtration Using Triboelectrification-Induced Electric Field.

Particulate matter (PM) in the environment can adversely affect the health of living things. However, high removal efficiency and low-pressure loss are crucial design challenges for any air filtration system. To circumvent the challenge, here, we demonstrate a novel triboelectric (TE) air filtration system that is based on a rotation-type triboelectric nanogenerator (TENG) and a filter comprising two sets of plates: primary and secondary, that are placed in the airflow channel. When the TENG charges the two plate sets with opposite charges, the flowing air particles are charged at the primary plates and are collected, due to an electric field, at the secondary plates. The TE filter has demonstrated a PM2.5 removal efficiency of ~ 99.97% for the fine dust particles, and it remains stable even after several washing cycles. The pressure loss is almost two orders less than the high-efficiency particulate air filter. Since the airflow itself can drive the TENG, the TE filter can potentially be integrated with any air conditioning system for fine dust filtration in offices, automobiles, etc.

Triboelectrification induced self-powered microbial disinfection using nanowire-enhanced localized electric field.

Air-transmitted pathogens may cause severe epidemics showing huge threats to public health. Microbial inactivation in the air is essential, whereas the feasibility of existing air disinfection technologies meets challenges including only achieving physical separation but no inactivation, obvious pressure drops, and energy intensiveness. Here we report a rapid disinfection method toward air-transmitted bacteria and viruses using the nanowire-enhanced localized electric field to damage the outer structures of microbes. This air disinfection system is driven by a triboelectric nanogenerator that converts mechanical vibration to electricity effectively and achieves self-powered. Assisted by a rational design for the accelerated charging and trapping of microbes, this air disinfection system promotes microbial transport and achieves high performance: >99.99% microbial inactivation within 0.025 s in a fast airflow (2 m/s) while only causing low pressure drops (<24 Pa). This rapid, self-powered air disinfection method may fill the urgent need for air-transmitted microbial inactivation to protect public health.