Catalysts can be obtained from renewable materials and/or materials that are otherwise viewed as waste. Although these materials are often inexpensive and readily available, using impure feedstocks introduces challenges because of both the variable compositions, and the presence of components that impact the catalytically active species. The interactions between species can be complex, and unexpected results – positive or negative - can be obtained. For example, the contaminant sulfur enhanced the recycling of potassium for the activation of carbon materials, while silicon and aluminum contaminants deactivated potassium in the catalytic gasification of coal. Knowledge of the composition and structure of the waste are critical. In petroleum coke, which is a byproduct of the heavy oil industry, the aromatic hydrogen groups can be accessed through ball-milling and then sulfonated to produce solid acid catalysts. Alternatively, it may be possible to directly use the sulfur inherent in the petroleum coke to form various catalysts and more fully utilize the waste.