THE SYNTHESIS OF AMMONIA OVER A RUTHENIUM SINGLE-CRYSTAL

The ammonia synthesis rate over a ruthenium single crystal has been st udied in the temperature range 598-898 K. Ammonia was synthesized from a stoichiometric (3H(2) : N-2) gas-mixture at a pressure of approxima tely 2 bar. The ammonia production rate was measured in two ways: with the reactor isolated (batch mode) and under constant gas flow (flow m ode). The overall activation energy was measured to be 101 +/- 4 kJ/mo l, and the turnover frequency was 2 x 10(-2) s(-1) at 673 K. After syn thesis, the primary adsorbed species was nitrogen and there was eviden ce of hydrogen in the bulk of the crystal. (C) 1998 Academic Press.