I'm not sure how to interpret 向学 in these 2 sentences。I think that 向 and 学/学习 work together.
1) 小张一心向学,厉志要成为一名科学家。'一心向学' = 1 mind to study = single-mindedly (to) study??
1) is from iciba and they give the translation as: Xiao Zhang works very hard to be a scientist.
看到孟子向有礼貌的人学习礼仪 = see Mengzi from have manners people learn etiquette = saw that Mengzi was learning etiquette from people with good manners
Do 向, 学习 work together?
I seem to have 2 different meanings in English 1) to study and in 2) learn from.