Plasma chemical synthesis. II. Effect of wall surface on the synthesis of ammonia
Plasma chemical synthesis. II. Effect of wall surface on the synthesis of ammonia
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DOI：
10.1007/bf01016001
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发表时间：
1987-03
影响因子：
3.6
通讯作者：
M. Touvelle;J. Licea;M. Venugopalan
中科院分区：
文献类型：
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作者：
M. Touvelle;J. Licea;M. Venugopalan
使用耐热玻璃和冷却至 77 K 的银表面，在 1-5 托的压力和高达 200 托 cm3min−1 的流速下研究了氨的等离子体合成。在余辉被捕获在耐热玻璃表面上的实验中，N 转化为氨的比例约为 13%。通过淬灭等离子体而不是余辉，使用 Pyrex 表面的氮转化百分比可以增加一倍，使用银表面可以增加四倍。增加氢气压力和/或氢气排放清洁降低了氮转化率；氮气排放调节无明显效果。随着氮气流量的增加，在银表面的淬灭等离子体反应中，氮转化率线性下降，这表明氮化和氢还原形成氨。 Pyrex 表面淬灭余辉反应中 N 转化百分比呈指数下降的原因是吸附 N2 的形成和/或解离，决定了 77 K 下的氨产量。
The plasma synthesis of ammonia was stuided at pressures of 1–5 torr and flow rates of up to 200 torr cm3min−1using Pyrex and silver surfaces cooled to 77 K. The N conversion to ammonia was about 13% in experiments in which the afterglow was trapped on the Pyrex surface. By quenching the plasma rather than the afterglow, the percent N conversion could be doubled using the Pyrex surface and quadrupled using the silver surface. Increasing the hydrogen pressure and/or hydrogen discharge cleaning decreased the percent N conversion; nitrogen discharge conditioning had no significant effect. With increasing nitrogen flow rate the percent N conversion decreased linearly in the quenched plasma reaction on the silver surface, suggesting nitriding and reduction by hydrogen to form ammonia. The exponential decrease of the percent N conversion in the quenched afterglow reaction on the Pyrex surface is explained by the formation and/or dissociation of adsorbed N2determining the ammonia yield at 77 K.