HZSM-5 supported CuO-ZnO-Al2O3 nanocatalyst was synthesized through combustion method to be used in direct syngas to dimethyl ether conversion process. The nanocatalysts were synthesized in various citric acid/nitrates molar ratios of 0.5, 1, 2 and 4 to address the optimized ratio. The effect of this ratio was investigated on the catalytic properties using further techniques; hence, the phase evolution, morphology, functional groups, surface area and reducibility were investigated via XRD, FESEM, FTIR, BET and H-2-TPR, respectively. According to the analytical results, increasing the fuel/nitrates ratio enhances the morphological properties, and reducibility. It is found that increasing the ratio results interesting cave shaped porous morphology decorated by combustion exhaust gases forming a micro-porous structure. The H-2-TPR analysis indicates reducibility enhancement after increasing the fuel content. The performance test of direct syngas to DME conversion was carried out under variable operational conditions of 10-40 bar, 225-300 degrees C and fixed conditions of GHSV = 600 cm(3)/g h and H-2/CO = 2 M ratio. The catalytic performance tests are resulted the highest catalytic activity for the sample with the fuel/nitrates molar ratio of 4 (CZAZ4) among the prepared samples through all the operating conditions. Furthermore, the performance test demonstrates the best catalytic activity for direct syngas to dimethyl ether reaction, at 300 degrees C and 40 bar. The time on the stream test of the CZAZ4 nanocatalyst is studied during the process of syngas to DME conversion with a consequence of negligible activity loss over 700 min stability test. (C) 2016 Elsevier Ltd. All rights reserved.