文献速递|耶鲁大学Jae-Hong Kim EST:基于过一硫酸盐的电化学高级氧化：氧还原反应的复杂性

第一作者：Hyun Jeong Lim

通讯作者：Jae-Hong Kim

通讯单位：耶鲁大学

DOI：10.1021/acs.est.3c06156

Figure 1. (a) PMS decomposition and (b) pCBA degradation in the N-CNT cathode system. Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 2.5 mM PMS, ORR eliminated by N2 purging of the electrolyte (with N2 purging for the absence of ORR and without N2 purging for the presence of ORR), applied potential of −0.5 V, temperature of 25 ± 1 °C. LSV scans with varying amounts of PMS on the N-CNT cathode (c) with N2 purging (absence of ORR) and (d) with O2 purging (presence of ORR). LSV scans with varying amounts of PMS on the CNT cathode (e) with N2 purging (absence of ORR) and (f) with O2 purging (presence of ORR). Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 0, 1, 4, and 8 mM PMS, temperature of 25 ± 1 °C. Note that the ohmic drop was negligible in this system on the basis of the observation depicted in Figure S7.

Figure 2. (a) LSV ring and disk currents of bare glassy carbon, CNT, and N-CNT-deposited glassy carbon and (b) calculated H2O2 selectivity (%) from the results of panel a. (c) Electrochemically generated H2O2 concentration without N2 purging (presence of ORR) with the N-CNT cathode. Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 2.5 mM PMS, applied potential of −0.5 V, temperature of 25 ± 1 °C.

Figure 3. (a) pH of the electrolyte during electrolysis with and without N2 purging. Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 2.5 mM PMS, applied potential of −0.5 V, temperature of 25 ± 1 °C. (b) pCBA degradation and (c) PMS decomposition at different pH values of the electrolyte in the presence of ORR. (d) H2O2 concentration resulting from ORR with and without PMS. Conditions: 50 mM phosphate buffer (electrolyte) with different pH values (3, 5, 7, 9, and 11), 25 μM pCBA, 2.5 mM PMS, applied potential of −0.5 V, temperature of 25 ± 1 °C.

Figure 4. pCBA degradation with EtOH (50 mM) and TBA (50 mM) as radical scavengers in an electrolyte (a) in the presence of ORR without N2 purging and (b) in the absence of ORR with N2 purging. Without scavenger plots is the duplication of data in Figure 1b. (c) Generation of hTPA from the reaction of •OH and TPA in electrolysis with and without N2 purging. Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 2.5 mM PMS, 0.5 mM TPA, applied potential of −0.5 V, temperature of 25 ± 1 °C. (d) In situ EPR analysis of SO4•– and •OH in an electrolyte in the presence of ORR. Conditions: microwave frequency of 9.83 GHz, microwave power of 6.325 mW, modulation frequency of 100 kHz, modulation amplitude of 1.0 G, sweep time of 30 s, 50 mM Na2SO4 (electrolyte), 2.5 mM PMS, 100 mM DMPO, applied potential of −0.5 V, temperature of 25 ± 1 °C.

Figure 5. pCBA degradation with PMS and varying H2O2 (a) without the electrode and (b) with current in the absence of ORR (with N2 purging). Conditions: 50 mM Na2SO4 (electrolyte), 25 μM pCBA, 2.5 mM PMS, 1, 2.5, 5, and 10 mM H2O2, 5 mM for H2O2 only condition, applied potential of −0.5 V, temperature of 25 ± 1 °C. (c) H2O2 decomposition in the mixture with PMS and Co ion. Conditions: background solution of 50 mM Na2SO4, 2.5 mM PMS, 1 mM H2O2, 50 μM Co2+, initial pH adjusted to 7.

Figure 6. Schematic of the interaction pathway and reactive species in the PMS-based EAOP in the absence and presence of ORR.