K-promoted bimetallic NiCo-NiAl2O4 nanocatalysts with various loadings of potassium (0, 0.25, 0.75 and 1.25) were fabricated by utilization of hybrid sol-gel plasma method. Nanocatalysts were assessed by XRD, FESEM, AFM, EDX, BET-BJH and TPR analyses. Also, used nanocatalysts were tested by TG-DTG, XRD, and EDX analyses. Nanocatalysts were appraised in O-2-enhanced dry reforming of CH4. XRD patterns indicated that by increasing of K loadings, amorphous behaviour was amplified. However, intensity of all peaks was decreased but reduction amount in the case of prone planes for coke formation slightly was greater than others. Great surface area and uniform dispersion was gained for the non-promoted nanocatalyst (NCKOA (SGP)), but surface covering by K addition led to the unsuitable properties. Owing to the EDX and FESEM, for K rich samples, surface area was decreased, average particle size got larger and dispersion of particles got worse. Noted attributes led to the lower yields of syngas for K rich samples. Despite the adverse impact of K such as lower activity, covering of defected site, enhanced reducibility and improving the rate of carbon gasification, led to the improved stability and less amount of coke deposition for K rich ones. Efficiency of NCKOA (SGP) and 0.25 wt% K promoted one (NCK0.25A (SGP)) were close to each other, but lower amount of deposited coke and more stable performance was gained for NCK0.25A (SGP). However, H-2 yields of NCKOA (SGP) and NCK0.25A (SGP) at first tests of TOF was close to each other but due to the 48 h test, they reached to 73 and 75%, respectively. Yields drop of NCKOA (SGP) was 8.5% while for NCK0.25A (SGP) was just 2.8%. Based on opposite tendency of TOF and yields and also, excellent properties of NCK0.25A (SGP) such as high enough activity, stable performance and high coke resistance, it seems that NCK0.25A (SGP) is a promising nanocatalyst for O-2-enhanced dry reforming of CH4. H-2 yield of NCK0.25A (SGP) at 850 degrees C was 87%. Small average particle size, tunable morphology, larger surface area and optimum amount of appended K, were the reasons which led to the superior performance of NCK0.25A (SGP). (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.