TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Conditions: The reaction conditions are maintained at 600-2000degreesC and 100-32000 kPa for a residence time of 200 milliseconds.Preferred Catalyst: The active metal is selected from iron, cobalt, nickel, rhenium, zirconium, ruthenium, rhodium, palladium, osmium, iridium, thorium or platinum. The promoter comprises a rare earth metal such as samarium or lanthanum. The support consists of alumina or zirconia. The catalyst comprises 1 ppm or more preferably 10 ppm, more preferably 100 ppm or more of halide. The halide comprises chloride or fluoride, and includes a non-metal halide compound such as hydrochloric acid or ammonium chloride.Preferred Method: Preparing a synthesis gas catalyst involves forming a promoter oxy halide on the support. The promoter oxy halide is samarium oxy chloride. Preparing synthesis gas catalyst involves depositing rare earth metal precursor, halide and active metal precursor on support, sequentially or simultaneously, by impregnation, co-precipitation and/or chemical vapor deposition, preferably by impregnation. The method further involves reducing the support after calcination. SPECIFIC COMPOUNDS - The active metal is rhodium. The promoter is samarium and the refractory support comprises alumina. The halide is chloride.    EXAMPLE - About 24.1 g of samarium nitrate (Sm(NO3)36H2O) was dissolved in water to form an aqueous solution. Alumina spheres of 1 mm average diameter were immersed into the solution for wet impregnation and dried under vacuum in a water bath at 70degreesC using a rotary evaporator. The impregnated spheres were calcined in air. 19.817 g of rhodium chloride was dissolved in water to form an aqueous solution. The calcined samarium content spheres, were immersed in rhodium chloride solution, dried, and calcined. The material was reduced at 500degreesC for 3 hours under mixed stream of 300 ml/minute each of hydrogen and nitrogen. A catalyst containing 4% rhodium and 4% samarium supported on 1 mm alumina sphere, was obtained. Partial oxidation reaction was carried out. Natural gas and oxygen in a molar ratio of 1.75:1 was reacted at gas hourly space velocity of 700000 hour-1, under pressure of 45 psig (412 kPa). The product gas mixture was analyzed. Carbon monoxide and hydrogen product selectivity, were 95.8% and 93.4%, respectively.