Abstract: 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穖in^-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穐)^-1 to 5.20 g?(kW穐)^-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.

Key words: inert gas, hydrogen peroxide, plasma, hydrogen, oxygen

摘要： 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5.20 g·(kW·h)^-1(以100%H₂O₂计)。发射光谱表征发现,在H₂-O₂-Ar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。

关键词: 惰性气体, 过氧化氢, 等离子体, 氢气, 氧气