Here we detail a new invention for how a bimetallic Ni-Cu-CNT-catalyst can be optimally designed for thermocatalytic decomposition (TCD) of methane. Specifically, we describe how the tuning of i) Ni/Cu ratio, ii) metal particle size, and iii) operating temperature are key factors in influencing TCD activity, stability, and carbon coproduct morphology. We believe these two findings are potentially patentable features: 1. Catalyst deactivation is associated with metal particle sintering, increased Ni/Cu ratio, and choice of operating temperature. For example, a monometallic Ni/CNT catalyst quickly deactivates at operating temperatures >550 degrees C. Increasing amount of Cu addition to the Ni catalysts results in decreasing initial TCD activity, however, increasing catalyst stability (see Figure 1 in attached paper). Additionally, catalyst stability at increased operating temperatures ( >650 degrees C) is facilitated by Ni catalysts only with high Cu loadings. It is the optimization of metal particle size, Ni/Cu ratio, and operating temperature as key parameters that together influence performance for methane TCD. 2. Carbon co-product quality can be tuned through choice of Ni/Cu ratio and operating temperature. The carbon co-product is mainly composed of multiwalled carbon nanotube (MWCNTs). While Cu addition to Ni increases catalyst stability, it also diminishes the "quality" of the CNT product as determined by Raman spectroscopy However, only relatively small amounts of Cu addition is required to provide marked improvement to stability (see Figure 9 in the attached paper). Further, as the choice in operating temperature plays a key role in dictating catalyst stability, it also influences the resulting carbon quality. Taken together, a trade off in catalyst stability and quality of the carbon product can be made. This optimization would be dictated by the process economics and carbon co--product requirements for the end use application.