To further study the mechanism and identify the principal reducing agent, we investigated WO3 and TEMPO reduction in methanol solution under 100% hydrogen gas. Holzapfel et al. reported using platinum catalysts to reduce TEMPO, a stable radical solution, via a hydrogen spillover pathway. Similar to the WO3 hydrogenation, the TEMPO reduction results in a color change from its natural amber coloration to a water-white coloration. Both the HSPE and HAT mechanisms produce hydrogen radicals, we use TEMPO as a secondary confirmation to whether our HEB is able to indeed perform hydrogen spillover. The TEMPO compound necessitated a liquid medium, due to its volatility. The possibility of HSPE occurring in solution is still debated, particularly whether a hydrogen radical can transfer and remain stable, even in a non-reducible solution. HSPE being done in solution is still up for debate, whether it is possible for spillover to occur in solution whether a hydrogen radical is willing to spillover and be stable in solution, even if the solution is non-reducible. This heterogeneous catalysis was done with a suspended solid solution -WO3 and in a dissolved solution -TEMPO. The HEB and platinum catalysts were both able to hydrogenate both WO3 (Figure ) and TEMPO samples (Figure ). The changing from a gaseous environment to a liquid medium, meant that the reaction time needed to be increased as the rate of reaction was slowed down significantly, we increased the time from 1-hour to 48hours. While the HEB was able to readily hydrogenate the samples spiked with benzyl mercaptan, the pure platinum sample, expectedly was poisoned and was unable to perform its hydrogenation reaction. As expected, the borophene layer acted as a poison-resistant shield, where the pure platinum sample was left vulnerable to sulfur and was inevitably poisoned and deactivated catalytically (Figure ). We believe that our HEB is doing its hydrogenation catalysis through a hybrid HAT/HSPE mechanism reflective of its unique crystal structure. When we recreated the seminal hydrogen spillover paper by Khoobiar et al. and compared WO3 hydrogenation between the HEB and pure platinum, both HEB and platinum metal demonstrated HxWO3 formation, suggesting the HSPE mechanism and reinforcing the idea that the mechanism under identical conditions is occurring.