ESR（电子自旋共振）或EPR表征问题？

求助各位大神，小弟我做的石墨烯/铁掺杂TiO2光催化剂，审稿意见回复需要做ESR表征（意见的原文：(1) This article does not use instrument for detection of radical species which is decisive for the degradation process of MB, such as?OH or O2-. Some characterizing techniques, such as ESR measurements are wished to be performed to further support their proposed mechanism;）。看过一些文献后还是对ESR不太明了。请问我的固体催化剂做ESR的话（P25，铁掺杂TiO2，石墨烯/铁掺杂TiO2光催化剂）是不是要加自由基捕捉剂（如DMPO等，这个好像很贵的）？? ?光照多长时间较为合适？? ? Magnetic field (G)范围多少合适，除了?OH 和 O2-，正常的话Fe3+会不会也出峰呀？??谢谢！