Dealloyed nanoporous copper as a highly active catalyst in Fenton-like reaction for degradation of organic pollutants

Copper-based catalysts for persulfate-based oxidation are desired due to the low toxicity. Herein, nanoporous copper materials were fabricated by dealloying the aluminum-copper (Al-Cu) alloys. Bicontinuous interpenetrating ligament–channel structures containing zero-valent copper (Cu0) network with trace Cu2O on the surface were obtained by adjusting the dealloying conditions. The as-dealloyed nanoporous copper catalysts exhibited superior catalytic performances in peroxymonosulfate (PMS) activation towards the degradation of bisphenol A (BPA), compared with the commercial Cu0 and Cu2O nanoparticles or counterparts prepared by liquid precipitation methods. The unique structures of nanoporous copper provide more exposure of active sites and pathways for mass transfer. In addition, the copper network with good conductivity favors the electron transfer, and the ligaments with high-density low-coordinated sites are ready to interact with PMS. Assisted by the simulated sunlight, the degradation efficiency was greatly improved through photochemical oxidation, due to the synergistic effect of light irradiation and PMS. The free hydroxyl (•OH) and sulfate (SO4•−) radicals mainly contributed to the degradation of BPA in the chemical oxidation, while •OH, SO4•− and singlet oxygen (1O2) dominated the decomposition in the photochemical reaction. This study suggests that dealloying is an effective method for fabricating catalysts for persulfate-based oxidation, providing new insight in developing highly active catalysts for wastewater purification.