In double dielectric barrier discharge aqueous electrodes reactor (DDBD), hydrogen peroxide was prepared in a mixture of hydrogen and oxygen by using DBD discharge with inert gas (Ar, He and N2) as additive gas. The influence of different inert gases on the breakdown voltage and energy efficiency of H2O2 synthesis was studied. The results showed that breakdown voltage, conversion of O2 , selectivity of H2O2, yield of H2O2 and energy efficiency were obviously affected by different inert gases. The breakdown voltage could be reduced with He and Ar as additive gas, however, it became higher when N2 was the additive gas. On the other hand, energy efficiency of H2O2 synthesis was reduced dramatically with N2 as the additive gas, and little changed with He as the additive gas. However, energy efficiency of H2O2 synthesis increased markedly with Ar as the additive gas. When Ar flow rate was 56. 6 ml · min-1 , breakdown voltage could be reduced from 11. 8 kV to 10. 2 kV; energy efficiency of H2O2 synthesis increased by about 51%, from 3. 45 g · (kW · h)-1 to 5. 20 g · (kW · h)-1 (100% H2O2). Therefore, the addition of Ar could not only reduce breakdown voltage, but also increase energy efficiency of H2O2 synthesis. The optical emission spectra revealed that Penning ionization effects of metastable state Ar species (696. 5, 794. 8, 811. 5 nm) existing in H2-O2-Ar discharge system might be responsible for the decrease of breakdown voltage. From the waveform of discharge current, the addition of Ar increased electron density, which obviously facilitated the increase of O2 conversion and energy efficiency of H2O2 synthesis at the same power.%在H2/O2体系中添加惰性气体(Ar、He、N2)进行常压介质阻挡放电,合成了H2O2水溶液.系统研究了不同惰性气体对体系击穿电压及H2O2合成能效的影响.结果表明,添加气体对击穿电压、O2转化率、H2O2选择性、H2O2收率及能量效率能产生较大影响.其中Ar的引入不仅降低了击穿电压,还提高了合成H2O2的能量效率；当Ar添加量为56.6 ml·min-1时,击穿电压由11.8 kV降为10.2 kV;合成H2O2的能量效率提高51％,由3.45 g·(kW·h)-1提高至5.20g·(kW·h)-1(以100％H2O2计).发射光谱表征发现,在H 2O2Ar放电体系中存在以亚稳态为末态的辐射Ar (696.5、794.8、811.5 nm),表明亚稳态Ar物种的潘宁电离作用可能是降低击穿电压的主要因素.由示波器测量的放电电流波形图可知,Ar的加入增大了体系电子密度,使得相同功率下O2转化速率大幅提高,从而使合成H2O2能量效率显著提高.
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