A Fully Solar-Driven Microprocessor-Regulated Portable Cathodic Protection Device Incorporating a Highly Active Noble-Metal-Free Anode for Efficient Green Metal Protection

Cathodic protection (CP) is widely employed to mitigate metal corrosion for underground and marine facilities, but the implementation of conventional sacrificial anode CP (SACP) and impressed current CP (ICCP) is obstructed by drawbacks such as release of harmful substances, continuous external power supply, and complicated maintenance. Although solar-powered CP systems have emerged to replace conventional systems, the available technical routes are far from perfect: the efficiencies of semiconductor-based small photoelectrochemical devices are still low, and ICCP systems driven by photovoltaic (PV) cells are often large in size and high in cost. Herein, a portable CP device (30 × 30 × 20 cm³ and 5.1 kg) with a modular design has been constructed, the fully functioning of which is solely powered by a PV cell without any external electricity input. A real-time “monitoring-feedback-adjustment” mechanism was modulated by a cost-effective and multifunctional microprocessor to precisely maintain the metal potential within the protective potential range. Moreover, a lab-made noble-metal-free auxiliary anode composed of porous Ni foam coated with NiMo alloy was first introduced to the PV-driven ICCP system, which accelerated the water oxidation kinetics compared to various commercial anodes and elevated the overall energy efficiency. Consequently, the as-built SMPCPD was capable of providing continuous CP to three types of representative metals in natural seawater under outdoor sunlight illumination conditions. These findings represent a variable pathway to achieve CP of underwater and underground steel structures with zero carbon emission, no environmental toxicity, intelligent control, high-energy efficiency, and flexibility.