Mechanical friction energy is a ubiquitous green energy that can be collected and transformed into electrical energy for water treatment, a concept theoretically referred to as tribocatalysis. The efficient removal of organic pollutants from wastewater by tribocatalysis still faces challenges. Employing doping technology to introduce metallic elements into materials is anticipated to enhance tribocatalytic performance by improving material properties. In this work, NiO and x wt% Co-doped NiO (x = 3, 5, 7, and 9) nanocatalysts are prepared using a coprecipitation method. The incorporation of Co effectively reduces the bandgap of NiO, enhancing tribocatalytic decomposition performance through the synergistic effects of charge transfer and electron transition. Notably, the optimized 7 wt% Co–NiO nanoparticles demonstrate the leading performance in the decomposition of rhodamine B (RhB), with a decomposition ratio of 96.7% after 120 min, representing a 23.1% increase over pure NiO. Electrochemical impedance spectroscopy (EIS) demonstrates that Co doping reduces the charge transfer resistance of NiO, resulting in the production of more reactive species. Radical trapping experiments and electron paramagnetic resonance spectroscopy (ESR) reveal that both superoxide radicals (·O₂⁻) and holes (h⁺) are key active radicals in dye decomposition. Furthermore, the 7 wt% Co–NiO nanocatalyst exhibits excellent stability and magnetic recyclability, retaining an 87.1% decomposition ratio after five cycles. The Co–NiO nanocatalyst, with these advantages of excellent tribocatalysis performance, low cost, and magnetic recyclability, has potential for application in wastewater treatment through harvesting and utilizing environmental mechanical friction energy in the future.

The strong pyrocatalytic dye decomposition of the BaTiO₃/Pr₂O₃ heterojunction catalyst under cold–hot alternation conditions has been demonstrated in this work. For pure BaTiO₃ nanofibers, ~54% rhodamine B (RhB) dye is decomposed under the cold–hot alternation of 29–57 ℃. With the loading content of Pr₂O₃ increases from 0 to 4 wt%, the pyrocatalytic decomposition ratio of RhB solution increases first and then decreases, eventually achieving a maximum of 91% at 3 wt%. The enhanced pyrocatalytic performance after loading Pr₂O₃ can be attributed to an internal electric field of the heterojunction, which effectively separates positive and negative charges. The strongly pyrocatalytic performance of BaTiO₃/Pr₂O₃ makes it hopeful for applications in the dye wastewater treatment through harvesting the environmental cold–hot temperature alternation thermal energy in future.