The WLE system previously reported achieved productivity comparable with stirred tank reactors but lower efficiency. However, much higher productivity and efficiency was proposed with an optimized system. Very recently, also a similar approach using unencapsulated wirelesslypowered µLED in fixed bed has been proposed. This has the advantage of the higher packing density but hears significant risks of contamination and degradation of the electronics which are in direct contact with the reaction medium. The authors report STY on par with good microcapillary systems and propose an extremely high energy efficiency. However, the proposed PSTY of up to 1410 mmol d -1 W -1 , is an order of magnitude above the theoretical maximum, calling this claim into doubt. Nonetheless, this underlines the significant potential of wirelessly powered light emitters. Therefore, this contribution explored the limits in productivity and efficiency that can be achieved with the proposed WLE system with further optimization or the energy supply as well as number and makeup of the emitter units. As a case study, the heterogeneously catalyzed reduction of nitrobenzene in alcoholic solutions using titanium dioxide is explored to prove the feasibility and applicability to heterogeneous reaction mixtures. Experimental Details