The field’s signature plot: conversion vs temperature. Sweep the bed temperature and compare three schematic catalysts — the earlier-light-off formulation shows the lower T₅₀ under matched feed, flow, loading and conversion criteria; overall quality still needs selectivity, stability and transport checks.
Schematic sigmoid light-off curves X(T) = 1/(1+e−(T−T₅₀)/w) with teaching parameters — not data for any real catalyst or reaction. Real T₅₀ values shift with feed, flow and ramp rate; quote conditions with the number, and sense the bed itself (exotherms carry it above the setpoint exactly at ignition). A lower T₅₀ alone does not establish better overall catalyst quality — selectivity, stability and transport limitations also matter.