检测CO_2的脉冲电势调制库仑技术

Investigation of Pulse Potential-modulated Coulometry for CO_2 Detection

应用脉冲电势调制技术,通过控制电极电势可将CO2还原为以吸附COads为主的中间物;之后再将电极电势阶跃到该物种能发生电化学氧化的电势,测量它的暂态氧化电流,得到积分电量Q随被测CO2浓度C的变化关系.对给定的还原时间,在CO2浓度为0.015%～20%的范围内,氧化电量Q与CO2浓度C有确定的对应关系.其中,当还原时间较短及CO2浓度较低情况下,两者有近似线性关系.这是一种可在较宽浓度范围内测定CO2的简便有效方法.

A pulse potential-modulated technique was applied to measure the concentration of CO_2 in gas samples. In the first step, an anodic pulse and a consequent cathodic pulse were used to remove the organic pollutant and surface oxide on the surface of the platinized Pt gauze electrode before each experiment. As following, a given potential step was used to reduce the CO_2 into adsorbed intermediate on Pt surface, and the adsorbates produced were oxidized by a following anodic potential step. At same time the oxidation current of adsorbates were measured. A certain relation exists between the concentration of CO_2 and the oxidation charge within the concentration range of (0.015)% to 20%. The approximate linear concentration-charge relation appears during a shorter reduction period and at a lower concentration of CO_2. It's wide convenient and effective for the detection of CO_2 in a relatively wide concentration range.