Chen, D., Li, Y., Wei, Z., Xiao, Y., Cao, C., Xiao, D., Lee, C., Hsu, C., Wang, H., Han, L. (2026). Inside-out-engineered CuO x /Ru sites for efficient electrochemical nitrate reduction to ammonia. Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.2537982123