In order to further clarify the photocatalytic degradation mechanism of the PhACs over the 10 FeCuNiCoZn HEA under visible light irradiation, the dissociation intermediates were detected via LC-MS. In particular, the disintegration pathway of DCF was investigated in detail because 12 of its maximum removal amongst all the four PhACs. A total of twelve compounds were 13 identified for the photocatalytic degradation of DCF, as listed in Table , and the plausible NO3 -. In fact, up to 39% TOC removal is achieved after 120 min of irradiation (Fig. ),