Unlocking the electrocatalytic activity of natural chalcopyrite using mechanochemistry

Manipulating the structure self-reconstruction of transition metal sulfide-based(pre)catalysts during the oxygen evolution reaction(OER) process is of great interest for developing cost-effective OER catalysts,which remains a central challenge. Here we realize a deep structure self-reconstruction of natural chalcopyrite to unlock its OER performance via mechanochemical activation. Compared with the manually milled counterpart(CuFeS_(2)-HM), the mechanically milled catalyst(CuFeS_(2)-BM) with a reduced crystallinity exhibits a 7.11 times higher OER activity at 1.53 V vs. RHE. In addition, the CuFeS_(2)-BM requires a low overpotential of 243 mV for generating 10 mA cm^(-2) and exhibits good stability over 24 h. Further investigations suggest that the excellent OER performance of CuFeS_(2)-BM mainly originates from the decreased crystallinity induced the in situ deep structure self-reconstruction of the originally sulfides into the electroactive and stable metal(oxy)hydroxide phase(e.g., a-Fe OOH) via S etching under OER conditions. This study demonstrates that regulating the crystallinity of catalysts is a promising design strategy for developing highly efficient OER catalysts via managing the structure self-reconstruction process, which can be further extended to the design of efficient catalysts for other advanced energy conversion devices. In addition, this study unveils the great potentials of engineering abundant natural minerals as cost-effective catalysts for diverse applications.